+ +Read in different language : [**zh**](localization/zh/README.md), [**zh-TW**](localization/zh-TW/README.md) +,[**ko**](localization/ko/README.md), [**fr**](localization/fr/README.md), [**tr**](localization/tr/README.md), [**ar**](localization/ar/README.md), [**es**](localization/es/README.md), [**pt**](localization/pt/README.md), [**id**](localization/id/README.md), [**ru**](localization/ru/README.md), [**de**](localization/de/README.md), [**ja**](localization/ja/README.md), [**vi**](localization/vi/README.md), [**bn**](localization/bn/README.md), [**np**](localization/ne/README.md), [**it**](localization/it/README.md), [**da**](localization/da/README.md) +
# Introduction -Design patterns are formalized best practices that the programmer can use to -solve common problems when designing an application or system. +Design patterns are the best, formalized practices a programmer can use to solve common problems when designing an application or system. + +Design patterns can speed up the development process by providing tested, proven development paradigms. -Design patterns can speed up the development process by providing tested, proven -development paradigms. +Reusing design patterns helps prevent subtle issues that cause major problems, and it also improves code readability for coders and architects who are familiar with the patterns. -Reusing design patterns helps to prevent subtle issues that can cause major -problems, and it also improves code readability for coders and architects who -are familiar with the patterns. +# Getting Started -# Getting started +This site showcases Java Design Patterns. The solutions have been developed by experienced programmers and architects from the open-source community. The patterns can be browsed by their high-level descriptions or by looking at their +source code. The source code examples are well commented and can be thought of as programming tutorials on how to implement a specific pattern. We use the most popular battle-proven open-source Java technologies. -Before you dive into the material, you should be familiar with various -Programming/Software Design Principles. +Before you dive into the material, you should be familiar with various [Software Design Principles](https://java-design-patterns.com/principles/). -All designs should be as simple as possible. You should start with KISS, YAGNI, -and Do The Simplest Thing That Could Possibly Work principles. Complexity and -patterns should only be introduced when they are needed for practical -extensibility. +All designs should be as simple as possible. You should start with KISS, YAGNI, and Do The Simplest Thing That Could Possibly Work principles. Complexity and patterns should only be introduced when they are needed for practical extensibility. -Once you are familiar with these concepts you can start drilling down into -patterns by any of the following approaches +Once you are familiar with these concepts you can start drilling down into the [available design patterns](https://java-design-patterns.com/patterns/) by any of the following approaches: - - Using difficulty tags, `Difficulty-Beginner`, `Difficulty-Intermediate` & `Difficulty-Expert`. - - Using pattern categories, `Creational`, `Behavioral` and others. - - Search for a specific pattern. Can't find one? Please report a new pattern [here](https://github.com/iluwatar/java-design-patterns/issues). + - Search for a specific pattern by name. Can't find one? Please report a new pattern [here](https://github.com/iluwatar/java-design-patterns/issues). + - Using tags such as `Performance`, `Gang of Four` or `Data access`. + - Using pattern categories, `Creational`, `Behavioral`, and others. -# How to contribute +Hopefully, you find the object-oriented solutions presented on this site useful in your architectures and have as much fun learning them as we had while developing them. + +# How to Contribute If you are willing to contribute to the project you will find the relevant information in our [developer wiki](https://github.com/iluwatar/java-design-patterns/wiki). We will help you and answer your questions in the [Gitter chatroom](https://gitter.im/iluwatar/java-design-patterns). +# The Book + +The design patterns are now available as an e-book. Find out more about "Open Source Java Design Patterns" here: https://payhip.com/b/bNQFX + +The project contributors can get the book for free. Contact the maintainer via [Gitter chatroom](https://gitter.im/iluwatar/java-design-patterns) or email (iluwatar (at) gmail (dot) com ). Send a message that contains your email address, Github username, and a link to an accepted pull request. + # License This project is licensed under the terms of the MIT license. + +# Supporters + +
+
+ 
+ |
+
+ SerpApi+SerpApi is the world’s leading provider of search data, pioneering APIs that turn search engine results into structured, developer-ready information. + |
+
+ * Copyright © 2014-2022 Ilkka Seppälä + * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: - *
+ * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. - *
+ *
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
@@ -22,51 +24,78 @@
*/
package com.iluwatar.abstractdocument;
+import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Objects;
-import java.util.Optional;
import java.util.function.Function;
import java.util.stream.Stream;
-/**
- * Abstract implementation of Document interface
- */
+/** Abstract implementation of Document interface. */
public abstract class AbstractDocument implements Document {
- private final Map
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
- *
+ *
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
- *
+ *
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
@@ -23,69 +25,64 @@
package com.iluwatar.abstractdocument;
import com.iluwatar.abstractdocument.domain.Car;
-import com.iluwatar.abstractdocument.domain.HasModel;
-import com.iluwatar.abstractdocument.domain.HasParts;
-import com.iluwatar.abstractdocument.domain.HasPrice;
-import com.iluwatar.abstractdocument.domain.HasType;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-import java.util.Arrays;
-import java.util.HashMap;
+import com.iluwatar.abstractdocument.domain.enums.Property;
+import java.util.List;
import java.util.Map;
+import lombok.extern.slf4j.Slf4j;
/**
- * The Abstract Document pattern enables handling additional, non-static
- * properties. This pattern uses concept of traits to enable type safety and
- * separate properties of different classes into set of interfaces.
- *
- *
- * In Abstract Document pattern,({@link AbstractDocument}) fully implements
- * {@link Document}) interface. Traits are then defined to enable access to
- * properties in usual, static way.
+ * The Abstract Document pattern enables handling additional, non-static properties. This pattern
+ * uses concept of traits to enable type safety and separate properties of different classes into
+ * set of interfaces.
+ *
+ * In Abstract Document pattern,({@link AbstractDocument}) fully implements {@link Document})
+ * interface. Traits are then defined to enable access to properties in usual, static way.
*/
+@Slf4j
public class App {
- private static final Logger LOGGER = LoggerFactory.getLogger(App.class);
-
/**
- * Executes the App
+ * Program entry point.
+ *
+ * @param args command line args
*/
- public App() {
+ public static void main(String[] args) {
LOGGER.info("Constructing parts and car");
- Map
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
- *
+ *
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
- *
+ *
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
@@ -26,22 +28,20 @@
import java.util.function.Function;
import java.util.stream.Stream;
-/**
- * Document interface
- */
+/** Document interface. */
public interface Document {
/**
- * Puts the value related to the key
+ * Puts the value related to the key.
*
- * @param key element key
+ * @param key element key
* @param value element value
* @return Void
*/
Void put(String key, Object value);
/**
- * Gets the value for the key
+ * Gets the value for the key.
*
* @param key element key
* @return value or null
@@ -49,9 +49,9 @@ public interface Document {
Object get(String key);
/**
- * Gets the stream of child documents
+ * Gets the stream of child documents.
*
- * @param key element key
+ * @param key element key
* @param constructor constructor of child class
* @return child documents
*/
diff --git a/abstract-document/src/main/java/com/iluwatar/abstractdocument/domain/Car.java b/abstract-document/src/main/java/com/iluwatar/abstractdocument/domain/Car.java
index 44f640b415fd..93fbbb9c1eae 100644
--- a/abstract-document/src/main/java/com/iluwatar/abstractdocument/domain/Car.java
+++ b/abstract-document/src/main/java/com/iluwatar/abstractdocument/domain/Car.java
@@ -1,17 +1,19 @@
-/**
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
* The MIT License
- * Copyright (c) 2014-2016 Ilkka Seppälä
- *
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
- *
+ *
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
- *
+ *
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
@@ -22,17 +24,13 @@
*/
package com.iluwatar.abstractdocument.domain;
-import java.util.Map;
-
import com.iluwatar.abstractdocument.AbstractDocument;
+import java.util.Map;
-/**
- * Car entity
- */
+/** Car entity. */
public class Car extends AbstractDocument implements HasModel, HasPrice, HasParts {
public Car(Map
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
- *
+ *
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
- *
+ *
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
@@ -22,19 +24,14 @@
*/
package com.iluwatar.abstractdocument.domain;
-import java.util.Optional;
-
import com.iluwatar.abstractdocument.Document;
+import com.iluwatar.abstractdocument.domain.enums.Property;
+import java.util.Optional;
-/**
- * HasModel trait for static access to 'model' property
- */
+/** HasModel trait for static access to 'model' property. */
public interface HasModel extends Document {
- String PROPERTY = "model";
-
default Optional
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
- *
+ *
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
- *
+ *
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
@@ -22,19 +24,14 @@
*/
package com.iluwatar.abstractdocument.domain;
-import java.util.stream.Stream;
-
import com.iluwatar.abstractdocument.Document;
+import com.iluwatar.abstractdocument.domain.enums.Property;
+import java.util.stream.Stream;
-/**
- * HasParts trait for static access to 'parts' property
- */
+/** HasParts trait for static access to 'parts' property. */
public interface HasParts extends Document {
- String PROPERTY = "parts";
-
default Stream
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
- *
+ *
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
- *
+ *
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
@@ -22,19 +24,14 @@
*/
package com.iluwatar.abstractdocument.domain;
-import java.util.Optional;
-
import com.iluwatar.abstractdocument.Document;
+import com.iluwatar.abstractdocument.domain.enums.Property;
+import java.util.Optional;
-/**
- * HasPrice trait for static access to 'price' property
- */
+/** HasPrice trait for static access to 'price' property. */
public interface HasPrice extends Document {
- String PROPERTY = "price";
-
default Optional
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
- *
+ *
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
- *
+ *
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
@@ -23,18 +25,13 @@
package com.iluwatar.abstractdocument.domain;
import com.iluwatar.abstractdocument.Document;
-
+import com.iluwatar.abstractdocument.domain.enums.Property;
import java.util.Optional;
-/**
- * HasType trait for static access to 'type' property
- */
+/** HasType trait for static access to 'type' property. */
public interface HasType extends Document {
- String PROPERTY = "type";
-
default Optional
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
- *
+ *
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
- *
+ *
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
@@ -22,17 +24,13 @@
*/
package com.iluwatar.abstractdocument.domain;
-import java.util.Map;
-
import com.iluwatar.abstractdocument.AbstractDocument;
+import java.util.Map;
-/**
- * Part entity
- */
+/** Part entity. */
public class Part extends AbstractDocument implements HasType, HasModel, HasPrice {
public Part(Map
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
- *
+ *
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
- *
+ *
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
@@ -22,67 +24,107 @@
*/
package com.iluwatar.abstractdocument;
-import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.*;
-import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
-import java.util.stream.Stream;
+import org.junit.jupiter.api.Test;
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertNotNull;
-
-/**
- * AbstractDocument test class
- */
-public class AbstractDocumentTest {
+/** AbstractDocument test class */
+class AbstractDocumentTest {
private static final String KEY = "key";
private static final String VALUE = "value";
- private class DocumentImplementation extends AbstractDocument {
+ private static class DocumentImplementation extends AbstractDocument {
DocumentImplementation(Map
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
- *
+ *
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
- *
+ *
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
@@ -22,16 +24,21 @@
*/
package com.iluwatar.abstractdocument;
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+
import org.junit.jupiter.api.Test;
-/**
- * Simple App test
- */
-public class AppTest {
+/** Simple App test */
+class AppTest {
+ /**
+ * Issue: Add at least one assertion to this test case.
+ *
+ * Solution: Inserted assertion to check whether the execution of the main method in {@link
+ * App} throws an exception.
+ */
@Test
- public void shouldExecuteAppWithoutException() {
- App.main(null);
+ void shouldExecuteAppWithoutException() {
+ assertDoesNotThrow(() -> App.main(null));
}
-
}
diff --git a/abstract-document/src/test/java/com/iluwatar/abstractdocument/DomainTest.java b/abstract-document/src/test/java/com/iluwatar/abstractdocument/DomainTest.java
index 891e5a45763e..fc29dea45c43 100644
--- a/abstract-document/src/test/java/com/iluwatar/abstractdocument/DomainTest.java
+++ b/abstract-document/src/test/java/com/iluwatar/abstractdocument/DomainTest.java
@@ -1,17 +1,19 @@
-/**
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
* The MIT License
- * Copyright (c) 2014-2016 Ilkka Seppälä
- *
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
- *
+ *
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
- *
+ *
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
@@ -22,24 +24,17 @@
*/
package com.iluwatar.abstractdocument;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
import com.iluwatar.abstractdocument.domain.Car;
-import com.iluwatar.abstractdocument.domain.HasModel;
-import com.iluwatar.abstractdocument.domain.HasParts;
-import com.iluwatar.abstractdocument.domain.HasPrice;
-import com.iluwatar.abstractdocument.domain.HasType;
import com.iluwatar.abstractdocument.domain.Part;
-import org.junit.jupiter.api.Test;
-
-import java.util.Arrays;
-import java.util.HashMap;
+import com.iluwatar.abstractdocument.domain.enums.Property;
+import java.util.List;
import java.util.Map;
+import org.junit.jupiter.api.Test;
-import static org.junit.jupiter.api.Assertions.assertEquals;
-
-/**
- * Test for Part and Car
- */
-public class DomainTest {
+/** Test for Part and Car */
+class DomainTest {
private static final String TEST_PART_TYPE = "test-part-type";
private static final String TEST_PART_MODEL = "test-part-model";
@@ -49,29 +44,28 @@ public class DomainTest {
private static final long TEST_CAR_PRICE = 1L;
@Test
- public void shouldConstructPart() {
- Map
- * The essence of the Abstract Factory pattern is a factory interface ({@link KingdomFactory}) and its implementations (
- * {@link ElfKingdomFactory}, {@link OrcKingdomFactory}). The example uses both concrete implementations to create a
- * king, a castle and an army.
- *
+ * The Abstract Factory pattern provides a way to encapsulate a group of individual factories that
+ * have a common theme without specifying their concrete classes. In normal usage, the client
+ * software creates a concrete implementation of the abstract factory and then uses the generic
+ * interface of the factory to create the concrete objects that are part of the theme. The client
+ * does not know (or care) which concrete objects it gets from each of these internal factories,
+ * since it uses only the generic interfaces of their products. This pattern separates the details
+ * of implementation of a set of objects from their general usage and relies on object composition,
+ * as object creation is implemented in methods exposed in the factory interface.
+ *
+ * The essence of the Abstract Factory pattern is a factory interface ({@link KingdomFactory})
+ * and its implementations ( {@link ElfKingdomFactory}, {@link OrcKingdomFactory}). The example uses
+ * both concrete implementations to create a king, a castle, and an army.
*/
-public class App {
+@Slf4j
+@Getter
+public class App implements Runnable {
- private static final Logger LOGGER = LoggerFactory.getLogger(App.class);
-
- private King king;
- private Castle castle;
- private Army army;
+ private final Kingdom kingdom = new Kingdom();
/**
- * Creates kingdom
+ * Program entry point.
+ *
+ * @param args command line args
*/
- public void createKingdom(final KingdomFactory factory) {
- setKing(factory.createKing());
- setCastle(factory.createCastle());
- setArmy(factory.createArmy());
- }
-
- King getKing(final KingdomFactory factory) {
- return factory.createKing();
- }
-
- public King getKing() {
- return king;
- }
-
- private void setKing(final King king) {
- this.king = king;
- }
-
- Castle getCastle(final KingdomFactory factory) {
- return factory.createCastle();
- }
-
- public Castle getCastle() {
- return castle;
- }
-
- private void setCastle(final Castle castle) {
- this.castle = castle;
- }
-
- Army getArmy(final KingdomFactory factory) {
- return factory.createArmy();
- }
-
- public Army getArmy() {
- return army;
+ public static void main(String[] args) {
+ var app = new App();
+ app.run();
}
- private void setArmy(final Army army) {
- this.army = army;
+ @Override
+ public void run() {
+ LOGGER.info("elf kingdom");
+ createKingdom(Kingdom.FactoryMaker.KingdomType.ELF);
+ LOGGER.info(kingdom.getArmy().getDescription());
+ LOGGER.info(kingdom.getCastle().getDescription());
+ LOGGER.info(kingdom.getKing().getDescription());
+
+ LOGGER.info("orc kingdom");
+ createKingdom(Kingdom.FactoryMaker.KingdomType.ORC);
+ LOGGER.info(kingdom.getArmy().getDescription());
+ LOGGER.info(kingdom.getCastle().getDescription());
+ LOGGER.info(kingdom.getKing().getDescription());
}
/**
- * The factory of kingdom factories.
+ * Creates kingdom.
+ *
+ * @param kingdomType type of Kingdom
*/
- public static class FactoryMaker {
-
- /**
- * Enumeration for the different types of Kingdoms.
- */
- public enum KingdomType {
- ELF, ORC
- }
-
- /**
- * The factory method to create KingdomFactory concrete objects.
- */
- public static KingdomFactory makeFactory(KingdomType type) {
- switch (type) {
- case ELF:
- return new ElfKingdomFactory();
- case ORC:
- return new OrcKingdomFactory();
- default:
- throw new IllegalArgumentException("KingdomType not supported.");
- }
- }
- }
-
- /**
- * Program entry point.
- *
- * @param args
- * command line args
- */
- public static void main(String[] args) {
-
- App app = new App();
-
- LOGGER.info("Elf Kingdom");
- app.createKingdom(FactoryMaker.makeFactory(KingdomType.ELF));
- LOGGER.info(app.getArmy().getDescription());
- LOGGER.info(app.getCastle().getDescription());
- LOGGER.info(app.getKing().getDescription());
-
- LOGGER.info("Orc Kingdom");
- app.createKingdom(FactoryMaker.makeFactory(KingdomType.ORC));
- LOGGER.info(app.getArmy().getDescription());
- LOGGER.info(app.getCastle().getDescription());
- LOGGER.info(app.getKing().getDescription());
+ public void createKingdom(final Kingdom.FactoryMaker.KingdomType kingdomType) {
+ final KingdomFactory kingdomFactory = Kingdom.FactoryMaker.makeFactory(kingdomType);
+ kingdom.setKing(kingdomFactory.createKing());
+ kingdom.setCastle(kingdomFactory.createCastle());
+ kingdom.setArmy(kingdomFactory.createArmy());
}
-}
\ No newline at end of file
+}
diff --git a/abstract-factory/src/main/java/com/iluwatar/abstractfactory/Army.java b/abstract-factory/src/main/java/com/iluwatar/abstractfactory/Army.java
index 3d107dd3479e..78c75323f1c0 100644
--- a/abstract-factory/src/main/java/com/iluwatar/abstractfactory/Army.java
+++ b/abstract-factory/src/main/java/com/iluwatar/abstractfactory/Army.java
@@ -1,6 +1,8 @@
-/**
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
* The MIT License
- * Copyright (c) 2014-2016 Ilkka Seppälä
+ * Copyright © 2014-2022 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
@@ -22,11 +24,7 @@
*/
package com.iluwatar.abstractfactory;
-/**
- *
- * Army interface
- *
- */
+/** Army interface. */
public interface Army {
String getDescription();
diff --git a/abstract-factory/src/main/java/com/iluwatar/abstractfactory/Castle.java b/abstract-factory/src/main/java/com/iluwatar/abstractfactory/Castle.java
index 837952d0d364..ee1e16f3cd3f 100644
--- a/abstract-factory/src/main/java/com/iluwatar/abstractfactory/Castle.java
+++ b/abstract-factory/src/main/java/com/iluwatar/abstractfactory/Castle.java
@@ -1,6 +1,8 @@
-/**
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
* The MIT License
- * Copyright (c) 2014-2016 Ilkka Seppälä
+ * Copyright © 2014-2022 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
@@ -22,11 +24,7 @@
*/
package com.iluwatar.abstractfactory;
-/**
- *
- * Castle interface
- *
- */
+/** Castle interface. */
public interface Castle {
String getDescription();
diff --git a/abstract-factory/src/main/java/com/iluwatar/abstractfactory/ElfArmy.java b/abstract-factory/src/main/java/com/iluwatar/abstractfactory/ElfArmy.java
index f9687073df29..d7e46c1456f0 100644
--- a/abstract-factory/src/main/java/com/iluwatar/abstractfactory/ElfArmy.java
+++ b/abstract-factory/src/main/java/com/iluwatar/abstractfactory/ElfArmy.java
@@ -1,6 +1,8 @@
-/**
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
* The MIT License
- * Copyright (c) 2014-2016 Ilkka Seppälä
+ * Copyright © 2014-2022 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
@@ -22,14 +24,10 @@
*/
package com.iluwatar.abstractfactory;
-/**
- *
- * ElfArmy
- *
- */
+/** ElfArmy. */
public class ElfArmy implements Army {
- static final String DESCRIPTION = "This is the Elven Army!";
+ static final String DESCRIPTION = "This is the elven army!";
@Override
public String getDescription() {
diff --git a/abstract-factory/src/main/java/com/iluwatar/abstractfactory/ElfCastle.java b/abstract-factory/src/main/java/com/iluwatar/abstractfactory/ElfCastle.java
index 108bdc8d315a..136afb11fd23 100644
--- a/abstract-factory/src/main/java/com/iluwatar/abstractfactory/ElfCastle.java
+++ b/abstract-factory/src/main/java/com/iluwatar/abstractfactory/ElfCastle.java
@@ -1,6 +1,8 @@
-/**
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
* The MIT License
- * Copyright (c) 2014-2016 Ilkka Seppälä
+ * Copyright © 2014-2022 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
@@ -22,14 +24,10 @@
*/
package com.iluwatar.abstractfactory;
-/**
- *
- * ElfCastle
- *
- */
+/** ElfCastle. */
public class ElfCastle implements Castle {
- static final String DESCRIPTION = "This is the Elven castle!";
+ static final String DESCRIPTION = "This is the elven castle!";
@Override
public String getDescription() {
diff --git a/abstract-factory/src/main/java/com/iluwatar/abstractfactory/ElfKing.java b/abstract-factory/src/main/java/com/iluwatar/abstractfactory/ElfKing.java
index f6e400bc0d8c..9b0d3a6f1a77 100644
--- a/abstract-factory/src/main/java/com/iluwatar/abstractfactory/ElfKing.java
+++ b/abstract-factory/src/main/java/com/iluwatar/abstractfactory/ElfKing.java
@@ -1,6 +1,8 @@
-/**
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
* The MIT License
- * Copyright (c) 2014-2016 Ilkka Seppälä
+ * Copyright © 2014-2022 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
@@ -22,14 +24,10 @@
*/
package com.iluwatar.abstractfactory;
-/**
- *
- * ElfKing
- *
- */
+/** ElfKing. */
public class ElfKing implements King {
- static final String DESCRIPTION = "This is the Elven king!";
+ static final String DESCRIPTION = "This is the elven king!";
@Override
public String getDescription() {
diff --git a/abstract-factory/src/main/java/com/iluwatar/abstractfactory/ElfKingdomFactory.java b/abstract-factory/src/main/java/com/iluwatar/abstractfactory/ElfKingdomFactory.java
index 31cfddb70ff8..b09a2f47c252 100644
--- a/abstract-factory/src/main/java/com/iluwatar/abstractfactory/ElfKingdomFactory.java
+++ b/abstract-factory/src/main/java/com/iluwatar/abstractfactory/ElfKingdomFactory.java
@@ -1,6 +1,8 @@
-/**
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
* The MIT License
- * Copyright (c) 2014-2016 Ilkka Seppälä
+ * Copyright © 2014-2022 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
@@ -22,23 +24,21 @@
*/
package com.iluwatar.abstractfactory;
-/**
- *
- * ElfKingdomFactory concrete factory.
- *
- */
+/** ElfKingdomFactory concrete factory. */
public class ElfKingdomFactory implements KingdomFactory {
+ @Override
public Castle createCastle() {
return new ElfCastle();
}
+ @Override
public King createKing() {
return new ElfKing();
}
+ @Override
public Army createArmy() {
return new ElfArmy();
}
-
}
diff --git a/abstract-factory/src/main/java/com/iluwatar/abstractfactory/King.java b/abstract-factory/src/main/java/com/iluwatar/abstractfactory/King.java
index bffc994d24cb..9f65ed434577 100644
--- a/abstract-factory/src/main/java/com/iluwatar/abstractfactory/King.java
+++ b/abstract-factory/src/main/java/com/iluwatar/abstractfactory/King.java
@@ -1,6 +1,8 @@
-/**
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
* The MIT License
- * Copyright (c) 2014-2016 Ilkka Seppälä
+ * Copyright © 2014-2022 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
@@ -22,11 +24,7 @@
*/
package com.iluwatar.abstractfactory;
-/**
- *
- * King interface
- *
- */
+/** King interface. */
public interface King {
String getDescription();
diff --git a/abstract-factory/src/main/java/com/iluwatar/abstractfactory/Kingdom.java b/abstract-factory/src/main/java/com/iluwatar/abstractfactory/Kingdom.java
new file mode 100644
index 000000000000..d1f85a6a4812
--- /dev/null
+++ b/abstract-factory/src/main/java/com/iluwatar/abstractfactory/Kingdom.java
@@ -0,0 +1,56 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.abstractfactory;
+
+import lombok.Getter;
+import lombok.Setter;
+
+/** Helper class to manufacture {@link KingdomFactory} beans. */
+@Getter
+@Setter
+public class Kingdom {
+
+ private King king;
+ private Castle castle;
+ private Army army;
+
+ /** The factory of kingdom factories. */
+ public static class FactoryMaker {
+
+ /** Enumeration for the different types of Kingdoms. */
+ public enum KingdomType {
+ ELF,
+ ORC
+ }
+
+ /** The factory method to create KingdomFactory concrete objects. */
+ public static KingdomFactory makeFactory(KingdomType type) {
+ return switch (type) {
+ case ELF -> new ElfKingdomFactory();
+ case ORC -> new OrcKingdomFactory();
+ };
+ }
+ }
+}
diff --git a/abstract-factory/src/main/java/com/iluwatar/abstractfactory/KingdomFactory.java b/abstract-factory/src/main/java/com/iluwatar/abstractfactory/KingdomFactory.java
index fb3434fae136..199c6697dcaa 100644
--- a/abstract-factory/src/main/java/com/iluwatar/abstractfactory/KingdomFactory.java
+++ b/abstract-factory/src/main/java/com/iluwatar/abstractfactory/KingdomFactory.java
@@ -1,6 +1,8 @@
-/**
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
* The MIT License
- * Copyright (c) 2014-2016 Ilkka Seppälä
+ * Copyright © 2014-2022 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
@@ -22,11 +24,7 @@
*/
package com.iluwatar.abstractfactory;
-/**
- *
- * KingdomFactory factory interface.
- *
- */
+/** KingdomFactory factory interface. */
public interface KingdomFactory {
Castle createCastle();
@@ -34,5 +32,4 @@ public interface KingdomFactory {
King createKing();
Army createArmy();
-
}
diff --git a/abstract-factory/src/main/java/com/iluwatar/abstractfactory/OrcArmy.java b/abstract-factory/src/main/java/com/iluwatar/abstractfactory/OrcArmy.java
index 31552f4301db..31ed6896d921 100644
--- a/abstract-factory/src/main/java/com/iluwatar/abstractfactory/OrcArmy.java
+++ b/abstract-factory/src/main/java/com/iluwatar/abstractfactory/OrcArmy.java
@@ -1,6 +1,8 @@
-/**
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
* The MIT License
- * Copyright (c) 2014-2016 Ilkka Seppälä
+ * Copyright © 2014-2022 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
@@ -22,14 +24,10 @@
*/
package com.iluwatar.abstractfactory;
-/**
- *
- * OrcArmy
- *
- */
+/** OrcArmy. */
public class OrcArmy implements Army {
- static final String DESCRIPTION = "This is the Orc Army!";
+ static final String DESCRIPTION = "This is the orc army!";
@Override
public String getDescription() {
diff --git a/abstract-factory/src/main/java/com/iluwatar/abstractfactory/OrcCastle.java b/abstract-factory/src/main/java/com/iluwatar/abstractfactory/OrcCastle.java
index e72da4a77b50..bdae5709a97c 100644
--- a/abstract-factory/src/main/java/com/iluwatar/abstractfactory/OrcCastle.java
+++ b/abstract-factory/src/main/java/com/iluwatar/abstractfactory/OrcCastle.java
@@ -1,6 +1,8 @@
-/**
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
* The MIT License
- * Copyright (c) 2014-2016 Ilkka Seppälä
+ * Copyright © 2014-2022 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
@@ -22,14 +24,10 @@
*/
package com.iluwatar.abstractfactory;
-/**
- *
- * OrcCastle
- *
- */
+/** OrcCastle. */
public class OrcCastle implements Castle {
- static final String DESCRIPTION = "This is the Orc castle!";
+ static final String DESCRIPTION = "This is the orc castle!";
@Override
public String getDescription() {
diff --git a/abstract-factory/src/main/java/com/iluwatar/abstractfactory/OrcKing.java b/abstract-factory/src/main/java/com/iluwatar/abstractfactory/OrcKing.java
index f48115f89d3a..7f106d45a01d 100644
--- a/abstract-factory/src/main/java/com/iluwatar/abstractfactory/OrcKing.java
+++ b/abstract-factory/src/main/java/com/iluwatar/abstractfactory/OrcKing.java
@@ -1,6 +1,8 @@
-/**
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
* The MIT License
- * Copyright (c) 2014-2016 Ilkka Seppälä
+ * Copyright © 2014-2022 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
@@ -22,14 +24,10 @@
*/
package com.iluwatar.abstractfactory;
-/**
- *
- * OrcKing
- *
- */
+/** OrcKing. */
public class OrcKing implements King {
- static final String DESCRIPTION = "This is the Orc king!";
+ static final String DESCRIPTION = "This is the orc king!";
@Override
public String getDescription() {
diff --git a/abstract-factory/src/main/java/com/iluwatar/abstractfactory/OrcKingdomFactory.java b/abstract-factory/src/main/java/com/iluwatar/abstractfactory/OrcKingdomFactory.java
index 5b2ba3a30fc9..82d258570460 100644
--- a/abstract-factory/src/main/java/com/iluwatar/abstractfactory/OrcKingdomFactory.java
+++ b/abstract-factory/src/main/java/com/iluwatar/abstractfactory/OrcKingdomFactory.java
@@ -1,6 +1,8 @@
-/**
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
* The MIT License
- * Copyright (c) 2014-2016 Ilkka Seppälä
+ * Copyright © 2014-2022 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
@@ -22,21 +24,20 @@
*/
package com.iluwatar.abstractfactory;
-/**
- *
- * OrcKingdomFactory concrete factory.
- *
- */
+/** OrcKingdomFactory concrete factory. */
public class OrcKingdomFactory implements KingdomFactory {
+ @Override
public Castle createCastle() {
return new OrcCastle();
}
+ @Override
public King createKing() {
return new OrcKing();
}
+ @Override
public Army createArmy() {
return new OrcArmy();
}
diff --git a/abstract-factory/src/test/java/com/iluwatar/abstractfactory/AbstractFactoryTest.java b/abstract-factory/src/test/java/com/iluwatar/abstractfactory/AbstractFactoryTest.java
index 5940da6c1af3..b5dde940c464 100644
--- a/abstract-factory/src/test/java/com/iluwatar/abstractfactory/AbstractFactoryTest.java
+++ b/abstract-factory/src/test/java/com/iluwatar/abstractfactory/AbstractFactoryTest.java
@@ -1,6 +1,8 @@
-/**
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
* The MIT License
- * Copyright (c) 2014-2016 Ilkka Seppälä
+ * Copyright © 2014-2022 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
@@ -25,63 +27,66 @@
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertTrue;
-import com.iluwatar.abstractfactory.App.FactoryMaker;
-import com.iluwatar.abstractfactory.App.FactoryMaker.KingdomType;
-
-import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
-/**
- * Test for abstract factory
- */
-public class AbstractFactoryTest {
+/** Tests for abstract factory. */
+class AbstractFactoryTest {
- private App app = new App();
- private KingdomFactory elfFactory;
- private KingdomFactory orcFactory;
-
- @BeforeEach
- public void setUp() {
- elfFactory = FactoryMaker.makeFactory(KingdomType.ELF);
- orcFactory = FactoryMaker.makeFactory(KingdomType.ORC);
- }
+ private final App app = new App();
@Test
- public void king() {
- final King elfKing = app.getKing(elfFactory);
+ void verifyKingCreation() {
+ app.createKingdom(Kingdom.FactoryMaker.KingdomType.ELF);
+ final var kingdom = app.getKingdom();
+
+ final var elfKing = kingdom.getKing();
assertTrue(elfKing instanceof ElfKing);
assertEquals(ElfKing.DESCRIPTION, elfKing.getDescription());
- final King orcKing = app.getKing(orcFactory);
+
+ app.createKingdom(Kingdom.FactoryMaker.KingdomType.ORC);
+ final var orcKing = kingdom.getKing();
assertTrue(orcKing instanceof OrcKing);
assertEquals(OrcKing.DESCRIPTION, orcKing.getDescription());
}
@Test
- public void castle() {
- final Castle elfCastle = app.getCastle(elfFactory);
+ void verifyCastleCreation() {
+ app.createKingdom(Kingdom.FactoryMaker.KingdomType.ELF);
+ final var kingdom = app.getKingdom();
+
+ final var elfCastle = kingdom.getCastle();
assertTrue(elfCastle instanceof ElfCastle);
assertEquals(ElfCastle.DESCRIPTION, elfCastle.getDescription());
- final Castle orcCastle = app.getCastle(orcFactory);
+
+ app.createKingdom(Kingdom.FactoryMaker.KingdomType.ORC);
+ final var orcCastle = kingdom.getCastle();
assertTrue(orcCastle instanceof OrcCastle);
assertEquals(OrcCastle.DESCRIPTION, orcCastle.getDescription());
}
@Test
- public void army() {
- final Army elfArmy = app.getArmy(elfFactory);
+ void verifyArmyCreation() {
+ app.createKingdom(Kingdom.FactoryMaker.KingdomType.ELF);
+ final var kingdom = app.getKingdom();
+
+ final var elfArmy = kingdom.getArmy();
assertTrue(elfArmy instanceof ElfArmy);
assertEquals(ElfArmy.DESCRIPTION, elfArmy.getDescription());
- final Army orcArmy = app.getArmy(orcFactory);
+
+ app.createKingdom(Kingdom.FactoryMaker.KingdomType.ORC);
+ final var orcArmy = kingdom.getArmy();
assertTrue(orcArmy instanceof OrcArmy);
assertEquals(OrcArmy.DESCRIPTION, orcArmy.getDescription());
}
@Test
- public void createElfKingdom() {
- app.createKingdom(elfFactory);
- final King king = app.getKing();
- final Castle castle = app.getCastle();
- final Army army = app.getArmy();
+ void verifyElfKingdomCreation() {
+ app.createKingdom(Kingdom.FactoryMaker.KingdomType.ELF);
+ final var kingdom = app.getKingdom();
+
+ final var king = kingdom.getKing();
+ final var castle = kingdom.getCastle();
+ final var army = kingdom.getArmy();
assertTrue(king instanceof ElfKing);
assertEquals(ElfKing.DESCRIPTION, king.getDescription());
assertTrue(castle instanceof ElfCastle);
@@ -91,11 +96,13 @@ public void createElfKingdom() {
}
@Test
- public void createOrcKingdom() {
- app.createKingdom(orcFactory);
- final King king = app.getKing();
- final Castle castle = app.getCastle();
- final Army army = app.getArmy();
+ void verifyOrcKingdomCreation() {
+ app.createKingdom(Kingdom.FactoryMaker.KingdomType.ORC);
+ final var kingdom = app.getKingdom();
+
+ final var king = kingdom.getKing();
+ final var castle = kingdom.getCastle();
+ final var army = kingdom.getArmy();
assertTrue(king instanceof OrcKing);
assertEquals(OrcKing.DESCRIPTION, king.getDescription());
assertTrue(castle instanceof OrcCastle);
diff --git a/abstract-factory/src/test/java/com/iluwatar/abstractfactory/AppTest.java b/abstract-factory/src/test/java/com/iluwatar/abstractfactory/AppTest.java
index 80c2815dcc00..9f53691a594d 100644
--- a/abstract-factory/src/test/java/com/iluwatar/abstractfactory/AppTest.java
+++ b/abstract-factory/src/test/java/com/iluwatar/abstractfactory/AppTest.java
@@ -1,6 +1,8 @@
-/**
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
* The MIT License
- * Copyright (c) 2014-2016 Ilkka Seppälä
+ * Copyright © 2014-2022 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
@@ -22,17 +24,16 @@
*/
package com.iluwatar.abstractfactory;
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+
import org.junit.jupiter.api.Test;
-import java.io.IOException;
+/** Check whether the execution of the main method in {@link App} throws an exception. */
+class AppTest {
-/**
- * Tests that Abstract Factory example runs without errors.
- */
-public class AppTest {
@Test
- public void test() throws IOException {
- String[] args = {};
- App.main(args);
+ void shouldExecuteApplicationWithoutException() {
+
+ assertDoesNotThrow(() -> App.main(new String[] {}));
}
}
diff --git a/active-object/README.md b/active-object/README.md
new file mode 100644
index 000000000000..a804ce9e632b
--- /dev/null
+++ b/active-object/README.md
@@ -0,0 +1,222 @@
+---
+title: "Active Object Pattern in Java: Achieving Efficient Asynchronous Processing"
+shortTitle: Active Object
+description: "Learn about the Active Object design pattern in Java. This guide covers asynchronous behavior, concurrency, and practical examples to enhance your Java applications' performance."
+category: Concurrency
+language: en
+tag:
+ - Asynchronous
+ - Decoupling
+ - Messaging
+ - Synchronization
+ - Thread management
+---
+
+## Intent of Active Object Design Pattern
+
+The Active Object pattern provides a reliable method for asynchronous processing in Java, ensuring responsive applications and efficient thread management. It achieves this by encapsulating tasks within objects that have their own thread and message queue. This separation keeps the main thread responsive and avoids issues like direct thread manipulation or shared state access.
+
+## Detailed Explanation of Active Object Pattern with Real-World Examples
+
+Real-world example
+
+> Imagine a busy restaurant where customers place orders with waiters. Instead of the waiters going to the kitchen to prepare the food themselves, they write the orders on slips and hand them to a dispatcher. The dispatcher manages a pool of chefs who prepare the meals asynchronously. Once a chef is free, they pick up the next order from the queue, prepare the dish, and notify the waiter when it's ready for serving.
+>
+> In this analogy, the waiters represent the client threads, the dispatcher represents the scheduler, and the chefs represent the method execution in separate threads. This setup allows the waiters to continue taking orders without being blocked by the food preparation process, much like the Active Object pattern decouples method invocation from execution to enhance concurrency.
+
+In plain words
+
+> The Active Object pattern decouples method execution from method invocation to improve concurrency and responsiveness in multithreaded applications.
+
+Wikipedia says
+
+> The active object design pattern decouples method execution from method invocation for objects that each reside in their own thread of control.[1] The goal is to introduce concurrency, by using asynchronous method invocation and a scheduler for handling requests.
+>
+> The pattern consists of six elements:
+>
+> * A proxy, which provides an interface towards clients with publicly accessible methods.
+> * An interface which defines the method request on an active object.
+> * A list of pending requests from clients.
+> * A scheduler, which decides which request to execute next.
+> * The implementation of the active object method.
+> * A callback or variable for the client to receive the result.
+
+Sequence diagram
+
+
+
+
+## Programmatic Example of Active Object in Java
+
+This section explains how the Active Object design pattern works in Java, highlighting its use in asynchronous task management and concurrency control.
+
+The Orcs are known for their wildness and untameable soul. It seems like they have their own thread of control based on previous behavior. To implement a creature that has its own thread of control mechanism and expose its API only and not the execution itself, we can use the Active Object pattern.
+
+```java
+public abstract class ActiveCreature {
+ private final Logger logger = LoggerFactory.getLogger(ActiveCreature.class.getName());
+
+ private BlockingQueue In this example, we fire 20 threads to modify a value in the target class.
+ */
+public class App implements Runnable {
+
+ private static final Logger logger = LoggerFactory.getLogger(App.class.getName());
+
+ private static final int NUM_CREATURES = 3;
+
+ /**
+ * Program entry point.
+ *
+ * @param args command line arguments.
+ */
+ public static void main(String[] args) {
+ var app = new App();
+ app.run();
+ }
+
+ @Override
+ public void run() {
+ List In the Actor Model: - An **Actor** is an independent unit that has its own state and behavior.
+ * - Actors **communicate only through messages** — they do not share memory. - An **ActorSystem**
+ * is responsible for creating, starting, and managing the lifecycle of actors. - Messages are
+ * delivered asynchronously, and each actor processes them one at a time.
+ *
+ * 💡 Key benefits: - No shared memory = no need for complex thread-safety - Easy to scale with
+ * many actors - Suitable for highly concurrent or distributed systems
+ *
+ * 🔍 This example demonstrates the Actor Model: - `ActorSystem` starts two actors: `srijan` and
+ * `ansh`. - `ExampleActor` and `ExampleActor2` extend the `Actor` class and override the
+ * `onReceive()` method to handle messages. - Actors communicate using `send()` to pass `Message`
+ * objects that include the message content and sender's ID. - The actors process messages
+ * **asynchronously in separate threads**, and we allow a short delay (`Thread.sleep`) to let them
+ * run. - The system is shut down gracefully at the end.
+ */
+package com.iluwatar.actormodel;
+
+public class App {
+ public static void main(String[] args) throws InterruptedException {
+ ActorSystem system = new ActorSystem();
+ Actor srijan = new ExampleActor(system);
+ Actor ansh = new ExampleActor2(system);
+
+ system.startActor(srijan);
+ system.startActor(ansh);
+ ansh.send(new Message("Hello ansh", srijan.getActorId()));
+ srijan.send(new Message("Hello srijan!", ansh.getActorId()));
+
+ Thread.sleep(1000); // Give time for messages to process
+
+ srijan.stop(); // Stop the actor gracefully
+ ansh.stop();
+ system.shutdown(); // Stop the actor system
+ }
+}
diff --git a/actor-model/src/main/java/com/iluwatar/actormodel/ExampleActor.java b/actor-model/src/main/java/com/iluwatar/actormodel/ExampleActor.java
new file mode 100644
index 000000000000..fd49325f44bd
--- /dev/null
+++ b/actor-model/src/main/java/com/iluwatar/actormodel/ExampleActor.java
@@ -0,0 +1,53 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.actormodel;
+
+import java.util.ArrayList;
+import java.util.List;
+import lombok.Getter;
+import lombok.extern.slf4j.Slf4j;
+
+@Slf4j
+public class ExampleActor extends Actor {
+ private final ActorSystem actorSystem;
+ @Getter private final List In this example the visitor base class is {@link ModemVisitor}. The base class of the visited
+ * hierarchy is {@link Modem} and has two children {@link Hayes} and {@link Zoom} each one having
+ * its own visitor interface {@link HayesVisitor} and {@link ZoomVisitor} respectively. {@link
+ * ConfigureForUnixVisitor} and {@link ConfigureForDosVisitor} implement each derivative's visit
+ * method only if it is required
+ */
+public class App {
+
+ /** Program's entry point. */
+ public static void main(String[] args) {
+ var conUnix = new ConfigureForUnixVisitor();
+ var conDos = new ConfigureForDosVisitor();
+
+ var zoom = new Zoom();
+ var hayes = new Hayes();
+
+ hayes.accept(conDos); // Hayes modem with Dos configurator
+ zoom.accept(conDos); // Zoom modem with Dos configurator
+ hayes.accept(conUnix); // Hayes modem with Unix configurator
+ zoom.accept(conUnix); // Zoom modem with Unix configurator
+ }
+}
diff --git a/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ConfigureForDosVisitor.java b/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ConfigureForDosVisitor.java
new file mode 100644
index 000000000000..267a8d66ac45
--- /dev/null
+++ b/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ConfigureForDosVisitor.java
@@ -0,0 +1,44 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.acyclicvisitor;
+
+import lombok.extern.slf4j.Slf4j;
+
+/**
+ * ConfigureForDosVisitor class implements both zoom's and hayes' visit method for Dos manufacturer.
+ */
+@Slf4j
+public class ConfigureForDosVisitor implements AllModemVisitor {
+
+ @Override
+ public void visit(Hayes hayes) {
+ LOGGER.info(hayes + " used with Dos configurator.");
+ }
+
+ @Override
+ public void visit(Zoom zoom) {
+ LOGGER.info(zoom + " used with Dos configurator.");
+ }
+}
diff --git a/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ConfigureForUnixVisitor.java b/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ConfigureForUnixVisitor.java
new file mode 100644
index 000000000000..d9fd14f69435
--- /dev/null
+++ b/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ConfigureForUnixVisitor.java
@@ -0,0 +1,40 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.acyclicvisitor;
+
+import lombok.extern.slf4j.Slf4j;
+
+/**
+ * ConfigureForUnixVisitor class implements zoom's visit method for Unix manufacturer, unlike
+ * traditional visitor pattern, this class may selectively implement visit for other modems.
+ */
+@Slf4j
+public class ConfigureForUnixVisitor implements ZoomVisitor {
+
+ @Override
+ public void visit(Zoom zoom) {
+ LOGGER.info(zoom + " used with Unix configurator.");
+ }
+}
diff --git a/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/Hayes.java b/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/Hayes.java
new file mode 100644
index 000000000000..e0b2fcc2b530
--- /dev/null
+++ b/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/Hayes.java
@@ -0,0 +1,48 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.acyclicvisitor;
+
+import lombok.extern.slf4j.Slf4j;
+
+/** Hayes class implements its accept method. */
+@Slf4j
+public class Hayes implements Modem {
+
+ /** Accepts all visitors but honors only HayesVisitor. */
+ @Override
+ public void accept(ModemVisitor modemVisitor) {
+ if (modemVisitor instanceof HayesVisitor) {
+ ((HayesVisitor) modemVisitor).visit(this);
+ } else {
+ LOGGER.info("Only HayesVisitor is allowed to visit Hayes modem");
+ }
+ }
+
+ /** Hayes' modem's toString method. */
+ @Override
+ public String toString() {
+ return "Hayes modem";
+ }
+}
diff --git a/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/HayesVisitor.java b/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/HayesVisitor.java
new file mode 100644
index 000000000000..aad9b970994f
--- /dev/null
+++ b/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/HayesVisitor.java
@@ -0,0 +1,30 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.acyclicvisitor;
+
+/** HayesVisitor interface. */
+public interface HayesVisitor extends ModemVisitor {
+ void visit(Hayes hayes);
+}
diff --git a/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/Modem.java b/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/Modem.java
new file mode 100644
index 000000000000..8552574453e5
--- /dev/null
+++ b/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/Modem.java
@@ -0,0 +1,30 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.acyclicvisitor;
+
+/** //Modem abstract class. converted to an interface */
+public interface Modem {
+ void accept(ModemVisitor modemVisitor);
+}
diff --git a/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ModemVisitor.java b/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ModemVisitor.java
new file mode 100644
index 000000000000..9391a980cd29
--- /dev/null
+++ b/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ModemVisitor.java
@@ -0,0 +1,33 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.acyclicvisitor;
+
+/**
+ * ModemVisitor interface does not contain any visit methods so that it does not depend on the
+ * visited hierarchy. Each derivative's visit method is declared in its own visitor interface
+ */
+public interface ModemVisitor {
+ // Visitor is a degenerate base class for all visitors.
+}
diff --git a/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/Zoom.java b/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/Zoom.java
new file mode 100644
index 000000000000..59b50a54a12f
--- /dev/null
+++ b/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/Zoom.java
@@ -0,0 +1,48 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.acyclicvisitor;
+
+import lombok.extern.slf4j.Slf4j;
+
+/** Zoom class implements its accept method. */
+@Slf4j
+public class Zoom implements Modem {
+
+ /** Accepts all visitors but honors only ZoomVisitor. */
+ @Override
+ public void accept(ModemVisitor modemVisitor) {
+ if (modemVisitor instanceof ZoomVisitor) {
+ ((ZoomVisitor) modemVisitor).visit(this);
+ } else {
+ LOGGER.info("Only ZoomVisitor is allowed to visit Zoom modem");
+ }
+ }
+
+ /** Zoom modem's toString method. */
+ @Override
+ public String toString() {
+ return "Zoom modem";
+ }
+}
diff --git a/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ZoomVisitor.java b/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ZoomVisitor.java
new file mode 100644
index 000000000000..5388ded6f735
--- /dev/null
+++ b/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ZoomVisitor.java
@@ -0,0 +1,30 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.acyclicvisitor;
+
+/** ZoomVisitor interface. */
+public interface ZoomVisitor extends ModemVisitor {
+ void visit(Zoom zoom);
+}
diff --git a/acyclic-visitor/src/test/java/com/iluwatar/acyclicvisitor/AppTest.java b/acyclic-visitor/src/test/java/com/iluwatar/acyclicvisitor/AppTest.java
new file mode 100644
index 000000000000..7a21498a63ea
--- /dev/null
+++ b/acyclic-visitor/src/test/java/com/iluwatar/acyclicvisitor/AppTest.java
@@ -0,0 +1,45 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.acyclicvisitor;
+
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+
+import org.junit.jupiter.api.Test;
+
+/** Tests that the Acyclic Visitor example runs without errors. */
+class AppTest {
+
+ /**
+ * Issue: Add at least one assertion to this test case.
+ *
+ * Solution: Inserted assertion to check whether the execution of the main method in {@link
+ * App} throws an exception.
+ */
+ @Test
+ void shouldExecuteApplicationWithoutException() {
+
+ assertDoesNotThrow(() -> App.main(new String[] {}));
+ }
+}
diff --git a/acyclic-visitor/src/test/java/com/iluwatar/acyclicvisitor/HayesTest.java b/acyclic-visitor/src/test/java/com/iluwatar/acyclicvisitor/HayesTest.java
new file mode 100644
index 000000000000..a989d9287921
--- /dev/null
+++ b/acyclic-visitor/src/test/java/com/iluwatar/acyclicvisitor/HayesTest.java
@@ -0,0 +1,53 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.acyclicvisitor;
+
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.*;
+
+import org.junit.jupiter.api.Test;
+
+/** Hayes test class */
+class HayesTest {
+
+ @Test
+ void testAcceptForDos() {
+ var hayes = new Hayes();
+ var mockVisitor = mock(ConfigureForDosVisitor.class);
+
+ hayes.accept(mockVisitor);
+ verify((HayesVisitor) mockVisitor).visit(eq(hayes));
+ }
+
+ @Test
+ void testAcceptForUnix() {
+ var hayes = new Hayes();
+ var mockVisitor = mock(ConfigureForUnixVisitor.class);
+
+ hayes.accept(mockVisitor);
+
+ verifyNoMoreInteractions(mockVisitor);
+ }
+}
diff --git a/acyclic-visitor/src/test/java/com/iluwatar/acyclicvisitor/ZoomTest.java b/acyclic-visitor/src/test/java/com/iluwatar/acyclicvisitor/ZoomTest.java
new file mode 100644
index 000000000000..d5fe79965d47
--- /dev/null
+++ b/acyclic-visitor/src/test/java/com/iluwatar/acyclicvisitor/ZoomTest.java
@@ -0,0 +1,53 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.acyclicvisitor;
+
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+
+import org.junit.jupiter.api.Test;
+
+/** Zoom test class */
+class ZoomTest {
+
+ @Test
+ void testAcceptForDos() {
+ var zoom = new Zoom();
+ var mockVisitor = mock(ConfigureForDosVisitor.class);
+
+ zoom.accept(mockVisitor);
+ verify((ZoomVisitor) mockVisitor).visit(eq(zoom));
+ }
+
+ @Test
+ void testAcceptForUnix() {
+ var zoom = new Zoom();
+ var mockVisitor = mock(ConfigureForUnixVisitor.class);
+
+ zoom.accept(mockVisitor);
+ verify((ZoomVisitor) mockVisitor).visit(eq(zoom));
+ }
+}
diff --git a/adapter/README.md b/adapter/README.md
index e943baba52fd..489742494709 100644
--- a/adapter/README.md
+++ b/adapter/README.md
@@ -1,30 +1,31 @@
---
-layout: pattern
-title: Adapter
-folder: adapter
-permalink: /patterns/adapter/
-categories: Structural
-tags:
- - Java
- - Gang Of Four
- - Difficulty-Beginner
+title: "Adapter Pattern in Java: Seamless Integration of Incompatible Systems"
+shortTitle: Adapter
+description: "Learn how the Adapter Design Pattern works in Java with detailed examples and use cases. Understand how it enables compatibility between incompatible interfaces."
+category: Structural
+language: en
+tag:
+ - Compatibility
+ - Decoupling
+ - Gang of Four
+ - Interface
+ - Object composition
+ - Wrapping
---
## Also known as
-Wrapper
-## Intent
-Convert the interface of a class into another interface the clients
-expect. Adapter lets classes work together that couldn't otherwise because of
-incompatible interfaces.
+* Wrapper
-## Explanation
+## Intent of Adapter Design Pattern
-Real world example
+The Adapter Design Pattern in Java converts the interface of a class into another interface that clients expect, enabling compatibility.
-> Consider that you have some pictures in your memory card and you need to transfer them to your computer. In order to transfer them you need some kind of adapter that is compatible with your computer ports so that you can attach memory card to your computer. In this case card reader is an adapter.
-> Another example would be the famous power adapter; a three legged plug can't be connected to a two pronged outlet, it needs to use a power adapter that makes it compatible with the two pronged outlet.
-> Yet another example would be a translator translating words spoken by one person to another
+## Detailed Explanation of Adapter Pattern with Real-World Examples
+
+Real-world example
+
+> Consider that you have some pictures on your memory card and you need to transfer them to your computer. To transfer them, you need some kind of adapter that is compatible with your computer ports so that you can attach a memory card to your computer. In this case card reader is an adapter. Another example would be the famous power adapter; a three-legged plug can't be connected to a two-pronged outlet, it needs to use a power adapter that makes it compatible with the two-pronged outlets. Yet another example would be a translator translating words spoken by one person to another
In plain words
@@ -34,100 +35,120 @@ Wikipedia says
> In software engineering, the adapter pattern is a software design pattern that allows the interface of an existing class to be used as another interface. It is often used to make existing classes work with others without modifying their source code.
-**Programmatic Example**
+Sequence diagram
+
+
+
+## Programmatic Example of Adapter Pattern in Java
-Consider a captain that can only use rowing boats and cannot sail at all.
+The Adapter Pattern example in Java shows how a class with an incompatible interface can be adapted to work with another class.
-First we have interfaces `RowingBoat` and `FishingBoat`
+Consider a wannabe captain that can only use rowing boats but can't sail at all.
+
+First, we have interfaces `RowingBoat` and `FishingBoat`
```java
public interface RowingBoat {
- void row();
+ void row();
}
+@Slf4j
public class FishingBoat {
- private static final Logger LOGGER = LoggerFactory.getLogger(FishingBoat.class);
- public void sail() {
- LOGGER.info("The fishing boat is sailing");
- }
+ public void sail() {
+ LOGGER.info("The fishing boat is sailing");
+ }
}
```
-And captain expects an implementation of `RowingBoat` interface to be able to move
+The captain expects an implementation of `RowingBoat` interface to be able to move.
```java
-public class Captain implements RowingBoat {
+public class Captain {
- private RowingBoat rowingBoat;
+ private final RowingBoat rowingBoat;
- public Captain(RowingBoat rowingBoat) {
- this.rowingBoat = rowingBoat;
- }
+ // default constructor and setter for rowingBoat
+ public Captain(RowingBoat rowingBoat) {
+ this.rowingBoat = rowingBoat;
+ }
- @Override
- public void row() {
- rowingBoat.row();
- }
+ public void row() {
+ rowingBoat.row();
+ }
}
```
-Now let's say the pirates are coming and our captain needs to escape but there is only fishing boat available. We need to create an adapter that allows the captain to operate the fishing boat with his rowing boat skills.
+Now, let's say the pirates are coming and our captain needs to escape but there is only a fishing boat available. We need to create an adapter that allows the captain to operate the fishing boat with his rowing boat skills.
```java
+@Slf4j
public class FishingBoatAdapter implements RowingBoat {
- private static final Logger LOGGER = LoggerFactory.getLogger(FishingBoatAdapter.class);
-
- private FishingBoat boat;
+ private final FishingBoat boat;
- public FishingBoatAdapter() {
- boat = new FishingBoat();
- }
+ public FishingBoatAdapter() {
+ boat = new FishingBoat();
+ }
- @Override
- public void row() {
- boat.sail();
- }
+ @Override
+ public void row() {
+ boat.sail();
+ }
}
```
-And now the `Captain` can use the `FishingBoat` to escape the pirates.
+Now the `Captain` can use the `FishingBoat` to escape the pirates.
```java
-Captain captain = new Captain(new FishingBoatAdapter());
-captain.row();
+ public static void main(final String[] args) {
+ // The captain can only operate rowing boats but with adapter he is able to
+ // use fishing boats as well
+ var captain = new Captain(new FishingBoatAdapter());
+ captain.row();
+}
```
-## Applicability
-Use the Adapter pattern when
+The program outputs:
-* you want to use an existing class, and its interface does not match the one you need
-* you want to create a reusable class that cooperates with unrelated or unforeseen classes, that is, classes that don't necessarily have compatible interfaces
-* you need to use several existing subclasses, but it's impractical to adapt their interface by subclassing every one. An object adapter can adapt the interface of its parent class.
-* most of the applications using third party libraries use adapters as a middle layer between the application and the 3rd party library to decouple the application from the library. If another library has to be used only an adapter for the new library is required without having to change the application code.
+```
+10:25:08.074 [main] INFO com.iluwatar.adapter.FishingBoat -- The fishing boat is sailing
+```
+
+## When to Use the Adapter Pattern in Java
-## Consequences:
-Class and object adapters have different trade-offs. A class adapter
+Use the Adapter pattern in Java when
-* adapts Adaptee to Target by committing to a concrete Adaptee class. As a consequence, a class adapter won’t work when we want to adapt a class and all its subclasses.
-* let’s Adapter override some of Adaptee’s behavior, since Adapter is a subclass of Adaptee.
-* introduces only one object, and no additional pointer indirection is needed to get to the adaptee.
+* You want to use an existing class, and its interface does not match the one you need
+* You want to create a reusable class that cooperates with unrelated or unforeseen classes, that is, classes that don't necessarily have compatible interfaces
+* You need to use several existing subclasses, but it's impractical to adapt their interface by subclassing everyone. An object adapter can adapt the interface of its parent class.
+* Most of the applications using third-party libraries use adapters as a middle layer between the application and the 3rd party library to decouple the application from the library. If another library has to be used only an adapter for the new library is required without having to change the application code.
-An object adapter
+## Adapter Pattern Java Tutorials
-* let’s a single Adapter work with many Adaptees—that is, the Adaptee itself and all of its subclasses (if any). The Adapter can also add functionality to all Adaptees at once.
-* makes it harder to override Adaptee behavior. It will require subclassing Adaptee and making Adapter refer to the subclass rather than the Adaptee itself.
+* [Using the Adapter Design Pattern in Java (Dzone)](https://dzone.com/articles/adapter-design-pattern-in-java)
+* [Adapter in Java (Refactoring Guru)](https://refactoring.guru/design-patterns/adapter/java/example)
+* [The Adapter Pattern in Java (Baeldung)](https://www.baeldung.com/java-adapter-pattern)
+* [Adapter Design Pattern (GeeksForGeeks)](https://www.geeksforgeeks.org/adapter-pattern/)
+## Benefits and Trade-offs of Adapter Pattern
-## Real world examples
+Class and object adapters offer different benefits and drawbacks. A class adapter adapts the Adaptee to the Target by binding to a specific Adaptee class, which means it cannot adapt a class and all its subclasses. This type of adapter allows the Adapter to override some of the Adaptee’s behavior because the Adapter is a subclass of the Adaptee. Additionally, it introduces only one object without needing extra pointer indirection to reach the Adaptee.
+On the other hand, an object adapter allows a single Adapter to work with multiple Adaptees, including the Adaptee and all its subclasses. This type of adapter can add functionality to all Adaptees simultaneously. However, it makes overriding the Adaptee’s behavior more difficult, as it requires subclassing the Adaptee and having the Adapter refer to this subclass instead of the Adaptee itself.
+
+## Real-World Applications of Adapter Pattern in Java
+
+* `java.io.InputStreamReader` and `java.io.OutputStreamWriter` in the Java IO library.
+* GUI component libraries that allow for plug-ins or adapters to convert between different GUI component interfaces.
* [java.util.Arrays#asList()](http://docs.oracle.com/javase/8/docs/api/java/util/Arrays.html#asList%28T...%29)
* [java.util.Collections#list()](https://docs.oracle.com/javase/8/docs/api/java/util/Collections.html#list-java.util.Enumeration-)
* [java.util.Collections#enumeration()](https://docs.oracle.com/javase/8/docs/api/java/util/Collections.html#enumeration-java.util.Collection-)
* [javax.xml.bind.annotation.adapters.XMLAdapter](http://docs.oracle.com/javase/8/docs/api/javax/xml/bind/annotation/adapters/XmlAdapter.html#marshal-BoundType-)
+## References and Credits
-## Credits
-
-* [Design Patterns: Elements of Reusable Object-Oriented Software](http://www.amazon.com/Design-Patterns-Elements-Reusable-Object-Oriented/dp/0201633612)
-* [J2EE Design Patterns](http://www.amazon.com/J2EE-Design-Patterns-William-Crawford/dp/0596004273/ref=sr_1_2)
+* [Design Patterns: Elements of Reusable Object-Oriented Software](https://amzn.to/3w0pvKI)
+* [Effective Java](https://amzn.to/4cGk2Jz)
+* [Head First Design Patterns: Building Extensible and Maintainable Object-Oriented Software](https://amzn.to/49NGldq)
+* [J2EE Design Patterns](https://amzn.to/4dpzgmx)
+* [Refactoring to Patterns](https://amzn.to/3VOO4F5)
diff --git a/adapter/etc/adapter-sequence-diagram.png b/adapter/etc/adapter-sequence-diagram.png
new file mode 100644
index 000000000000..a9bb557ea61e
Binary files /dev/null and b/adapter/etc/adapter-sequence-diagram.png differ
diff --git a/adapter/etc/adapter.urm.png b/adapter/etc/adapter.urm.png
new file mode 100644
index 000000000000..341ad67699d9
Binary files /dev/null and b/adapter/etc/adapter.urm.png differ
diff --git a/adapter/etc/adapter.urm.puml b/adapter/etc/adapter.urm.puml
new file mode 100644
index 000000000000..1277cbb87125
--- /dev/null
+++ b/adapter/etc/adapter.urm.puml
@@ -0,0 +1,31 @@
+@startuml
+package com.iluwatar.adapter {
+ class App {
+ - App()
+ + main(args : String[]) {static}
+ }
+ class Captain {
+ - rowingBoat : RowingBoat
+ + Captain()
+ + Captain(boat : RowingBoat)
+ ~ row()
+ ~ setRowingBoat(boat : RowingBoat)
+ }
+ ~class FishingBoat {
+ - LOGGER : Logger {static}
+ ~ FishingBoat()
+ ~ sail()
+ }
+ class FishingBoatAdapter {
+ - boat : FishingBoat
+ + FishingBoatAdapter()
+ + row()
+ }
+ interface RowingBoat {
+ + row() {abstract}
+ }
+}
+FishingBoatAdapter --> "-boat" FishingBoat
+Captain --> "-rowingBoat" RowingBoat
+FishingBoatAdapter ..|> RowingBoat
+@enduml
\ No newline at end of file
diff --git a/adapter/pom.xml b/adapter/pom.xml
index 95ccee3a9d0f..6e7f45a515b5 100644
--- a/adapter/pom.xml
+++ b/adapter/pom.xml
@@ -1,8 +1,10 @@
-
+
-
- * There are two variations of the Adapter pattern: The class adapter implements the adaptee's
+ * There are two variations of the Adapter pattern: The class adapter implements the adaptee's
* interface whereas the object adapter uses composition to contain the adaptee in the adapter
* object. This example uses the object adapter approach.
*
- *
- * The Adapter ({@link FishingBoatAdapter}) converts the interface of the adaptee class (
- * {@link FishingBoat}) into a suitable one expected by the client ( {@link RowingBoat} ).
+ * The Adapter ({@link FishingBoatAdapter}) converts the interface of the adaptee class ({@link
+ * FishingBoat}) into a suitable one expected by the client ({@link RowingBoat}).
*
- *
- * The story of this implementation is this. The story of this implementation is this. An ambassador service can be thought of as an out-of-process proxy that is co-located with the
+ * client. Similar to the proxy design pattern, the ambassador service provides an interface for
+ * another remote service. In addition to the interface, the ambassador provides extra functionality
+ * and features, specifically offloaded common connectivity tasks. This usually consists of
+ * monitoring, logging, routing, security etc. This is extremely useful in legacy applications where
+ * the codebase is difficult to modify and allows for improvements in the application's networking
+ * capabilities.
+ *
+ * In this example, we will the ({@link ServiceAmbassador}) class represents the ambassador while
+ * the ({@link RemoteService}) class represents a remote application.
+ */
+public class App {
+
+ /** Entry point. */
+ public static void main(String[] args) {
+ var host1 = new Client();
+ var host2 = new Client();
+ host1.useService(12);
+ host2.useService(73);
+ }
+}
diff --git a/ambassador/src/main/java/com/iluwatar/ambassador/Client.java b/ambassador/src/main/java/com/iluwatar/ambassador/Client.java
new file mode 100644
index 000000000000..0baabf4ffc06
--- /dev/null
+++ b/ambassador/src/main/java/com/iluwatar/ambassador/Client.java
@@ -0,0 +1,40 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.ambassador;
+
+import lombok.extern.slf4j.Slf4j;
+
+/** A simple Client. */
+@Slf4j
+public class Client {
+
+ private final ServiceAmbassador serviceAmbassador = new ServiceAmbassador();
+
+ long useService(int value) {
+ var result = serviceAmbassador.doRemoteFunction(value);
+ LOGGER.info("Service result: {}", result);
+ return result;
+ }
+}
diff --git a/ambassador/src/main/java/com/iluwatar/ambassador/RemoteService.java b/ambassador/src/main/java/com/iluwatar/ambassador/RemoteService.java
new file mode 100644
index 000000000000..d99348040cfe
--- /dev/null
+++ b/ambassador/src/main/java/com/iluwatar/ambassador/RemoteService.java
@@ -0,0 +1,78 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.ambassador;
+
+import static java.lang.Thread.sleep;
+
+import com.iluwatar.ambassador.util.RandomProvider;
+import lombok.extern.slf4j.Slf4j;
+
+/** A remote legacy application represented by a Singleton implementation. */
+@Slf4j
+public class RemoteService implements RemoteServiceInterface {
+ private static final int THRESHOLD = 200;
+ private static RemoteService service = null;
+ private final RandomProvider randomProvider;
+
+ static synchronized RemoteService getRemoteService() {
+ if (service == null) {
+ service = new RemoteService();
+ }
+ return service;
+ }
+
+ private RemoteService() {
+ this(Math::random);
+ }
+
+ /** This constructor is used for testing purposes only. */
+ RemoteService(RandomProvider randomProvider) {
+ this.randomProvider = randomProvider;
+ }
+
+ /**
+ * Remote function takes a value and multiplies it by 10 taking a random amount of time. Will
+ * sometimes return -1. This imitates connectivity issues a client might have to account for.
+ *
+ * @param value integer value to be multiplied.
+ * @return if waitTime is less than {@link RemoteService#THRESHOLD}, it returns value * 10,
+ * otherwise {@link RemoteServiceStatus#FAILURE}.
+ */
+ @Override
+ public long doRemoteFunction(int value) {
+
+ long waitTime = (long) Math.floor(randomProvider.random() * 1000);
+
+ try {
+ sleep(waitTime);
+ } catch (InterruptedException e) {
+ LOGGER.error("Thread sleep state interrupted", e);
+ Thread.currentThread().interrupt();
+ }
+ return waitTime <= THRESHOLD
+ ? value * 10
+ : RemoteServiceStatus.FAILURE.getRemoteServiceStatusValue();
+ }
+}
diff --git a/ambassador/src/main/java/com/iluwatar/ambassador/RemoteServiceInterface.java b/ambassador/src/main/java/com/iluwatar/ambassador/RemoteServiceInterface.java
new file mode 100644
index 000000000000..aa6012bae33f
--- /dev/null
+++ b/ambassador/src/main/java/com/iluwatar/ambassador/RemoteServiceInterface.java
@@ -0,0 +1,31 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.ambassador;
+
+/** Interface shared by ({@link RemoteService}) and ({@link ServiceAmbassador}). */
+interface RemoteServiceInterface {
+
+ long doRemoteFunction(int value);
+}
diff --git a/ambassador/src/main/java/com/iluwatar/ambassador/RemoteServiceStatus.java b/ambassador/src/main/java/com/iluwatar/ambassador/RemoteServiceStatus.java
new file mode 100644
index 000000000000..8549ed7247f3
--- /dev/null
+++ b/ambassador/src/main/java/com/iluwatar/ambassador/RemoteServiceStatus.java
@@ -0,0 +1,44 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.ambassador;
+
+import lombok.Getter;
+
+/**
+ * Holds information regarding the status of the Remote Service.
+ *
+ * This Enum replaces the integer value previously stored in {@link RemoteServiceInterface} as
+ * SonarCloud was identifying it as an issue. All test cases have been checked after changes,
+ * without failures.
+ */
+public enum RemoteServiceStatus {
+ FAILURE(-1);
+
+ @Getter private final long remoteServiceStatusValue;
+
+ RemoteServiceStatus(long remoteServiceStatusValue) {
+ this.remoteServiceStatusValue = remoteServiceStatusValue;
+ }
+}
diff --git a/ambassador/src/main/java/com/iluwatar/ambassador/ServiceAmbassador.java b/ambassador/src/main/java/com/iluwatar/ambassador/ServiceAmbassador.java
new file mode 100644
index 000000000000..4d310169770b
--- /dev/null
+++ b/ambassador/src/main/java/com/iluwatar/ambassador/ServiceAmbassador.java
@@ -0,0 +1,83 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.ambassador;
+
+import static com.iluwatar.ambassador.RemoteServiceStatus.FAILURE;
+import static java.lang.Thread.sleep;
+
+import lombok.extern.slf4j.Slf4j;
+
+/**
+ * ServiceAmbassador provides an interface for a ({@link Client}) to access ({@link RemoteService}).
+ * The interface adds logging, latency testing and usage of the service in a safe way that will not
+ * add stress to the remote service when connectivity issues occur.
+ */
+@Slf4j
+public class ServiceAmbassador implements RemoteServiceInterface {
+
+ private static final int RETRIES = 3;
+ private static final int DELAY_MS = 3000;
+
+ ServiceAmbassador() {}
+
+ @Override
+ public long doRemoteFunction(int value) {
+ return safeCall(value);
+ }
+
+ private long checkLatency(int value) {
+ var startTime = System.currentTimeMillis();
+ var result = RemoteService.getRemoteService().doRemoteFunction(value);
+ var timeTaken = System.currentTimeMillis() - startTime;
+
+ LOGGER.info("Time taken (ms): {}", timeTaken);
+ return result;
+ }
+
+ private long safeCall(int value) {
+ var retries = 0;
+ var result = FAILURE.getRemoteServiceStatusValue();
+
+ for (int i = 0; i < RETRIES; i++) {
+ if (retries >= RETRIES) {
+ return FAILURE.getRemoteServiceStatusValue();
+ }
+
+ if ((result = checkLatency(value)) == FAILURE.getRemoteServiceStatusValue()) {
+ LOGGER.info("Failed to reach remote: ({})", i + 1);
+ retries++;
+ try {
+ sleep(DELAY_MS);
+ } catch (InterruptedException e) {
+ LOGGER.error("Thread sleep state interrupted", e);
+ Thread.currentThread().interrupt();
+ }
+ } else {
+ break;
+ }
+ }
+ return result;
+ }
+}
diff --git a/ambassador/src/main/java/com/iluwatar/ambassador/util/RandomProvider.java b/ambassador/src/main/java/com/iluwatar/ambassador/util/RandomProvider.java
new file mode 100644
index 000000000000..4eba2fada7fa
--- /dev/null
+++ b/ambassador/src/main/java/com/iluwatar/ambassador/util/RandomProvider.java
@@ -0,0 +1,30 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.ambassador.util;
+
+/** An interface for randomness. Useful for testing purposes. */
+public interface RandomProvider {
+ double random();
+}
diff --git a/ambassador/src/test/java/com/iluwatar/ambassador/AppTest.java b/ambassador/src/test/java/com/iluwatar/ambassador/AppTest.java
new file mode 100644
index 000000000000..ddb2d6eff411
--- /dev/null
+++ b/ambassador/src/test/java/com/iluwatar/ambassador/AppTest.java
@@ -0,0 +1,45 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.ambassador;
+
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+
+import org.junit.jupiter.api.Test;
+
+/** Application test */
+class AppTest {
+
+ /**
+ * Issue: Add at least one assertion to this test case.
+ *
+ * Solution: Inserted assertion to check whether the execution of the main method in {@link
+ * App} throws an exception.
+ */
+ @Test
+ void shouldExecuteApplicationWithoutException() {
+
+ assertDoesNotThrow(() -> App.main(new String[] {}));
+ }
+}
diff --git a/ambassador/src/test/java/com/iluwatar/ambassador/ClientTest.java b/ambassador/src/test/java/com/iluwatar/ambassador/ClientTest.java
new file mode 100644
index 000000000000..24603efff9d4
--- /dev/null
+++ b/ambassador/src/test/java/com/iluwatar/ambassador/ClientTest.java
@@ -0,0 +1,42 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.ambassador;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+/** Test for {@link Client} */
+class ClientTest {
+
+ @Test
+ void test() {
+ Client client = new Client();
+ var result = client.useService(10);
+
+ assertTrue(
+ result == 100 || result == RemoteServiceStatus.FAILURE.getRemoteServiceStatusValue());
+ }
+}
diff --git a/ambassador/src/test/java/com/iluwatar/ambassador/RemoteServiceTest.java b/ambassador/src/test/java/com/iluwatar/ambassador/RemoteServiceTest.java
new file mode 100644
index 000000000000..81e4f744128f
--- /dev/null
+++ b/ambassador/src/test/java/com/iluwatar/ambassador/RemoteServiceTest.java
@@ -0,0 +1,61 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.ambassador;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import com.iluwatar.ambassador.util.RandomProvider;
+import org.junit.jupiter.api.Test;
+
+/** Test for {@link RemoteService} */
+class RemoteServiceTest {
+
+ @Test
+ void testFailedCall() {
+ var remoteService = new RemoteService(new StaticRandomProvider(0.21));
+ var result = remoteService.doRemoteFunction(10);
+ assertEquals(RemoteServiceStatus.FAILURE.getRemoteServiceStatusValue(), result);
+ }
+
+ @Test
+ void testSuccessfulCall() {
+ var remoteService = new RemoteService(new StaticRandomProvider(0.2));
+ var result = remoteService.doRemoteFunction(10);
+ assertEquals(100, result);
+ }
+
+ private static class StaticRandomProvider implements RandomProvider {
+ private final double value;
+
+ StaticRandomProvider(double value) {
+ this.value = value;
+ }
+
+ @Override
+ public double random() {
+ return value;
+ }
+ }
+}
diff --git a/ambassador/src/test/java/com/iluwatar/ambassador/ServiceAmbassadorTest.java b/ambassador/src/test/java/com/iluwatar/ambassador/ServiceAmbassadorTest.java
new file mode 100644
index 000000000000..0543b2e7e370
--- /dev/null
+++ b/ambassador/src/test/java/com/iluwatar/ambassador/ServiceAmbassadorTest.java
@@ -0,0 +1,40 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.ambassador;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+/** Test for {@link ServiceAmbassador} */
+class ServiceAmbassadorTest {
+
+ @Test
+ void test() {
+ long result = new ServiceAmbassador().doRemoteFunction(10);
+ assertTrue(
+ result == 100 || result == RemoteServiceStatus.FAILURE.getRemoteServiceStatusValue());
+ }
+}
diff --git a/anti-corruption-layer/README.md b/anti-corruption-layer/README.md
new file mode 100644
index 000000000000..9b6042850eba
--- /dev/null
+++ b/anti-corruption-layer/README.md
@@ -0,0 +1,185 @@
+---
+title: "Anti-Corruption Layer Pattern in Java: Ensuring System Integrity Amidst Legacy Systems"
+shortTitle: Anti-Corruption Layer
+description: "Learn how the Anti-Corruption Layer design pattern helps in decoupling subsystems, preventing data corruption, and facilitating seamless integration in Java applications."
+category: Integration
+language: en
+tag:
+ - Architecture
+ - Decoupling
+ - Integration
+ - Isolation
+ - Layered architecture
+ - Migration
+ - Modernization
+ - Refactoring
+ - Wrapping
+---
+
+## Also known as
+
+* ACL
+* Interface layer
+* Translation layer
+
+## Intent of Anti-Corruption Layer Design Pattern
+
+The Anti-Corruption Layer (ACL) is a crucial design pattern in Java development, particularly for system integration and maintaining data integrity. Implement a façade or adapter layer between different subsystems that don't share the same semantics. It translates between different data formats and systems, ensuring that the integration between systems does not lead to corruption of business logic or data integrity.
+
+## Detailed Explanation of Anti-Corruption Layer Pattern with Real-World Examples
+
+Real-world example
+
+> This example demonstrates how the Anti-Corruption Layer ensures seamless integration between legacy systems and modern platforms, crucial for maintaining business logic integrity during system migration.
+>
+> Imagine a large retail company transitioning its inventory management system from an old legacy software to a new modern platform. The legacy system has been in use for decades and contains complex business rules and data formats that are incompatible with the new system. Instead of directly connecting the new system to the legacy one, the company implements an Anti-Corruption Layer (ACL).
+>
+> The ACL acts as a mediator, translating and adapting data between the two systems. When the new system requests inventory data, the ACL translates the request into a format the legacy system understands, retrieves the data, and then translates it back into a format suitable for the new system. This approach ensures that the new system remains unaffected by the intricacies of the legacy system, preventing corruption of data and business logic while facilitating a smooth transition.
+
+In plain words
+
+> The Anti-Corruption Layer design pattern protects a system from the complexities and changes of external systems by providing an intermediary translation layer.
+
+[Microsoft's documentation](https://learn.microsoft.com/en-us/azure/architecture/patterns/anti-corruption-layer) says
+
+> Implement a façade or adapter layer between different subsystems that don't share the same semantics. This layer translates requests that one subsystem makes to the other subsystem. Use this pattern to ensure that an application's design is not limited by dependencies on outside subsystems. This pattern was first described by Eric Evans in Domain-Driven Design.
+
+Sequence diagram
+
+
+
+## Programmatic Example of Anti-Corruption Layer Pattern in Java
+
+The ACL design pattern in Java provides an intermediary layer that translates data formats, ensuring that integration between different systems does not lead to data corruption.
+
+Here are 2 shop-ordering systems: `Legacy` and `Modern`.
+
+The aforementioned systems have different domain models and have to operate simultaneously. Since they work independently the orders can come either from the `Legacy` or `Modern` system. Therefore, the system that receives the legacyOrder needs to check if the legacyOrder is valid and not present in the other system. Then it can place the legacyOrder in its own system.
+
+But for that, the system needs to know the domain model of the other system and to avoid that, the anti-corruption layer(ACL) is introduced. The ACL is a layer that translates the domain model of the `Legacy` system to the domain model of the `Modern` system and vice versa. Also, it hides all other operations with the other system, uncoupling the systems.
+
+Domain model of the `Legacy` system:
+
+```java
+public class LegacyOrder {
+ private String id;
+ private String customer;
+ private String item;
+ private String qty;
+ private String price;
+}
+```
+
+Domain model of the `Modern` system:
+
+```java
+public class ModernOrder {
+ private String id;
+ private Customer customer;
+
+ private Shipment shipment;
+
+ private String extra;
+}
+
+public class Customer {
+ private String address;
+}
+
+public class Shipment {
+ private String item;
+ private String qty;
+ private String price;
+}
+```
+
+Anti-corruption layer:
+
+```java
+public class AntiCorruptionLayer {
+
+ @Autowired
+ private ModernShop modernShop;
+
+ @Autowired
+ private LegacyShop legacyShop;
+
+ public Optional Often these legacy systems suffer from quality issues such as convoluted data schemas or
+ * obsolete APIs. The features and technologies used in legacy systems can vary widely from more
+ * modern systems. To interoperate with the legacy system, the new application may need to support
+ * outdated infrastructure, protocols, data models, APIs, or other features that you wouldn't
+ * otherwise put into a modern application.
+ *
+ * Maintaining access between new and legacy systems can force the new system to adhere to at
+ * least some of the legacy system's APIs or other semantics. When these legacy features have
+ * quality issues, supporting them "corrupts" what might otherwise be a cleanly designed modern
+ * application. Similar issues can arise with any external system that your development team doesn't
+ * control, not just legacy systems.
+ *
+ * Solution Isolate the different subsystems by placing an anti-corruption layer between them.
+ * This layer translates communications between the two systems, allowing one system to remain
+ * unchanged while the other can avoid compromising its design and technological approach.
+ */
+package com.iluwatar.corruption;
diff --git a/anti-corruption-layer/src/main/java/com/iluwatar/corruption/system/AntiCorruptionLayer.java b/anti-corruption-layer/src/main/java/com/iluwatar/corruption/system/AntiCorruptionLayer.java
new file mode 100644
index 000000000000..4e8a17fa5d2a
--- /dev/null
+++ b/anti-corruption-layer/src/main/java/com/iluwatar/corruption/system/AntiCorruptionLayer.java
@@ -0,0 +1,66 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.corruption.system;
+
+import com.iluwatar.corruption.system.legacy.LegacyShop;
+import com.iluwatar.corruption.system.modern.Customer;
+import com.iluwatar.corruption.system.modern.ModernOrder;
+import com.iluwatar.corruption.system.modern.Shipment;
+import java.util.Optional;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+
+/**
+ * The class represents an anti-corruption layer. The main purpose of the class is to provide a
+ * layer between the modern and legacy systems. The class is responsible for converting the data
+ * from one system to another decoupling the systems to each other
+ *
+ * It allows using one system a domain model of the other system without changing the domain
+ * model of the system.
+ */
+@Service
+public class AntiCorruptionLayer {
+
+ @Autowired private LegacyShop legacyShop;
+
+ /**
+ * The method converts the order from the legacy system to the modern system.
+ *
+ * @param id the id of the order
+ * @return the order in the modern system
+ */
+ public Optional
- * The intent of the API Gateway pattern is to alleviate some of these issues. In the API Gateway
- * pattern, an additional entity (the API Gateway) is placed between the client and the
- * microservices. The job of the API Gateway is to aggregate the calls to the microservices.
- * Rather than the client calling each microservice individually, the client calls the API Gateway
- * a single time. The API Gateway then calls each of the microservices that the client needs.
- *
- *
- * This implementation shows what the API Gateway pattern could look like for an e-commerce site.
- * The {@link ApiGateway} makes calls to the Image and Price microservices using the
- * {@link ImageClientImpl} and {@link PriceClientImpl} respectively. Customers viewing the site on a
- * desktop device can see both price information and an image of a product, so the {@link ApiGateway}
- * calls both of the microservices and aggregates the data in the {@link DesktopProduct} model.
- * However, mobile users only see price information; they do not see a product image. For mobile
- * users, the {@link ApiGateway} only retrieves price information, which it uses to populate the
- * {@link MobileProduct}.
- */
-@SpringBootApplication
-public class App {
-
- /**
- * Program entry point
- *
- * @param args
- * command line args
- */
- public static void main(String[] args) {
- SpringApplication.run(App.class, args);
- }
-}
diff --git a/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/DesktopProduct.java b/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/DesktopProduct.java
deleted file mode 100644
index e72b98e73c40..000000000000
--- a/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/DesktopProduct.java
+++ /dev/null
@@ -1,54 +0,0 @@
-/**
- * The MIT License
- * Copyright (c) 2014-2016 Ilkka Seppälä
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-package com.iluwatar.api.gateway;
-
-/**
- * Encapsulates all of the information that a desktop client needs to display a product.
- */
-public class DesktopProduct {
- /**
- * The price of the product
- */
- private String price;
-
- /**
- * The path to the image of the product
- */
- private String imagePath;
-
- public String getPrice() {
- return price;
- }
-
- public void setPrice(String price) {
- this.price = price;
- }
-
- public String getImagePath() {
- return imagePath;
- }
-
- public void setImagePath(String imagePath) {
- this.imagePath = imagePath;
- }
-}
diff --git a/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/ImageClientImpl.java b/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/ImageClientImpl.java
deleted file mode 100644
index ebabfe839b69..000000000000
--- a/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/ImageClientImpl.java
+++ /dev/null
@@ -1,56 +0,0 @@
-/**
- * The MIT License
- * Copyright (c) 2014-2016 Ilkka Seppälä
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-package com.iluwatar.api.gateway;
-
-import org.apache.http.client.methods.CloseableHttpResponse;
-import org.apache.http.client.methods.HttpGet;
-import org.apache.http.impl.client.CloseableHttpClient;
-import org.apache.http.impl.client.HttpClients;
-import org.apache.http.util.EntityUtils;
-import org.springframework.stereotype.Component;
-
-import java.io.IOException;
-
-/**
- * An adapter to communicate with the Image microservice
- */
-@Component
-public class ImageClientImpl implements ImageClient {
- /**
- * Makes a simple HTTP Get request to the Image microservice
- * @return The path to the image
- */
- @Override
- public String getImagePath() {
- String response = null;
- try (CloseableHttpClient httpClient = HttpClients.createDefault()) {
- HttpGet httpGet = new HttpGet("http://localhost:50005/image-path");
- try (CloseableHttpResponse httpResponse = httpClient.execute(httpGet)) {
- response = EntityUtils.toString(httpResponse.getEntity());
- }
- } catch (IOException e) {
- e.printStackTrace();
- }
- return response;
- }
-}
diff --git a/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/PriceClientImpl.java b/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/PriceClientImpl.java
deleted file mode 100644
index 87f44761c649..000000000000
--- a/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/PriceClientImpl.java
+++ /dev/null
@@ -1,56 +0,0 @@
-/**
- * The MIT License
- * Copyright (c) 2014-2016 Ilkka Seppälä
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-package com.iluwatar.api.gateway;
-
-import org.apache.http.client.methods.CloseableHttpResponse;
-import org.apache.http.client.methods.HttpGet;
-import org.apache.http.impl.client.CloseableHttpClient;
-import org.apache.http.impl.client.HttpClients;
-import org.apache.http.util.EntityUtils;
-import org.springframework.stereotype.Component;
-
-import java.io.IOException;
-
-/**
- * An adapter to communicate with the Price microservice
- */
-@Component
-public class PriceClientImpl implements PriceClient {
- /**
- * Makes a simple HTTP Get request to the Price microservice
- * @return The price of the product
- */
- @Override
- public String getPrice() {
- String response = null;
- try (CloseableHttpClient httpClient = HttpClients.createDefault()) {
- HttpGet httpGet = new HttpGet("http://localhost:50006/price");
- try (CloseableHttpResponse httpResponse = httpClient.execute(httpGet)) {
- response = EntityUtils.toString(httpResponse.getEntity());
- }
- } catch (IOException e) {
- e.printStackTrace();
- }
- return response;
- }
-}
diff --git a/api-gateway/api-gateway-service/src/main/resources/application.properties b/api-gateway/api-gateway-service/src/main/resources/application.properties
deleted file mode 100644
index ae91c5eb5625..000000000000
--- a/api-gateway/api-gateway-service/src/main/resources/application.properties
+++ /dev/null
@@ -1,24 +0,0 @@
-#
-# The MIT License
-# Copyright (c) 2014-2016 Ilkka Seppälä
-#
-# Permission is hereby granted, free of charge, to any person obtaining a copy
-# of this software and associated documentation files (the "Software"), to deal
-# in the Software without restriction, including without limitation the rights
-# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-# copies of the Software, and to permit persons to whom the Software is
-# furnished to do so, subject to the following conditions:
-#
-# The above copyright notice and this permission notice shall be included in
-# all copies or substantial portions of the Software.
-#
-# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-# THE SOFTWARE.
-#
-
-server.port=50004
\ No newline at end of file
diff --git a/api-gateway/api-gateway-service/src/test/java/com/iluwatar/api/gateway/ApiGatewayTest.java b/api-gateway/api-gateway-service/src/test/java/com/iluwatar/api/gateway/ApiGatewayTest.java
deleted file mode 100644
index a86d991c8eda..000000000000
--- a/api-gateway/api-gateway-service/src/test/java/com/iluwatar/api/gateway/ApiGatewayTest.java
+++ /dev/null
@@ -1,81 +0,0 @@
-/**
- * The MIT License
- * Copyright (c) 2014-2016 Ilkka Seppälä
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-package com.iluwatar.api.gateway;
-
-import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Test;
-import org.mockito.InjectMocks;
-import org.mockito.Mock;
-import org.mockito.MockitoAnnotations;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.mockito.Mockito.when;
-
-/**
- * Test API Gateway Pattern
- */
-public class ApiGatewayTest {
-
- @InjectMocks
- private ApiGateway apiGateway;
-
- @Mock
- private ImageClient imageClient;
-
- @Mock
- private PriceClient priceClient;
-
- @BeforeEach
- public void setup() {
- MockitoAnnotations.initMocks(this);
- }
-
- /**
- * Tests getting the data for a desktop client
- */
- @Test
- public void testGetProductDesktop() {
- String imagePath = "/product-image.png";
- String price = "20";
- when(imageClient.getImagePath()).thenReturn(imagePath);
- when(priceClient.getPrice()).thenReturn(price);
-
- DesktopProduct desktopProduct = apiGateway.getProductDesktop();
-
- assertEquals(price, desktopProduct.getPrice());
- assertEquals(imagePath, desktopProduct.getImagePath());
- }
-
- /**
- * Tests getting the data for a mobile client
- */
- @Test
- public void testGetProductMobile() {
- String price = "20";
- when(priceClient.getPrice()).thenReturn(price);
-
- MobileProduct mobileProduct = apiGateway.getProductMobile();
-
- assertEquals(price, mobileProduct.getPrice());
- }
-}
diff --git a/api-gateway/image-microservice/pom.xml b/api-gateway/image-microservice/pom.xml
deleted file mode 100644
index e90747eb90e5..000000000000
--- a/api-gateway/image-microservice/pom.xml
+++ /dev/null
@@ -1,84 +0,0 @@
-
-
- It breaks tests down into three clear and distinct steps:
+ *
+ * 1. Arrange: Perform the setup and initialization required for the test.
+ *
+ * 2. Act: Take action(s) required for the test.
+ *
+ * 3. Assert: Verify the outcome(s) of the test.
+ *
+ * This pattern has several significant benefits. It creates a clear separation between a test's
+ * setup, operations, and results. This structure makes the code easier to read and understand. If
+ * you place the steps in order and format your code to separate them, you can scan a test and
+ * quickly comprehend what it does.
+ *
+ * It also enforces a certain degree of discipline when you write your tests. You have to think
+ * clearly about the three steps your test will perform. But it makes tests more natural to write at
+ * the same time since you already have an outline.
+ *
+ * In ({@link CashAAATest}) we have four test methods. Each of them has only one reason to change
+ * and one reason to fail. In a large and complicated code base, tests that honor the single
+ * responsibility principle are much easier to troubleshoot.
+ */
+class CashAAATest {
+
+ @Test
+ void testPlus() {
+ // Arrange
+ var cash = new Cash(3);
+ // Act
+ cash.plus(4);
+ // Assert
+ assertEquals(7, cash.count());
+ }
+
+ @Test
+ void testMinus() {
+ // Arrange
+ var cash = new Cash(8);
+ // Act
+ var result = cash.minus(5);
+ // Assert
+ assertTrue(result);
+ assertEquals(3, cash.count());
+ }
+
+ @Test
+ void testInsufficientMinus() {
+ // Arrange
+ var cash = new Cash(1);
+ // Act
+ var result = cash.minus(6);
+ // Assert
+ assertFalse(result);
+ assertEquals(1, cash.count());
+ }
+
+ @Test
+ void testUpdate() {
+ // Arrange
+ var cash = new Cash(5);
+ // Act
+ cash.plus(6);
+ var result = cash.minus(3);
+ // Assert
+ assertTrue(result);
+ assertEquals(8, cash.count());
+ }
+}
diff --git a/arrange-act-assert/src/test/java/com/iluwatar/arrangeactassert/CashAntiAAATest.java b/arrange-act-assert/src/test/java/com/iluwatar/arrangeactassert/CashAntiAAATest.java
new file mode 100644
index 000000000000..5756822516b8
--- /dev/null
+++ b/arrange-act-assert/src/test/java/com/iluwatar/arrangeactassert/CashAntiAAATest.java
@@ -0,0 +1,60 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.arrangeactassert;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * ({@link CashAAATest}) is an anti-example of AAA pattern. This test is functionally correct, but
+ * with the addition of a new feature, it needs refactoring. There are an awful lot of steps in that
+ * test method, but it verifies the class' important behavior in just eleven lines. It violates the
+ * single responsibility principle. If this test method failed after a small code change, it might
+ * take some digging to discover why.
+ */
+class CashAntiAAATest {
+
+ @Test
+ void testCash() {
+ // initialize
+ var cash = new Cash(3);
+ // test plus
+ cash.plus(4);
+ assertEquals(7, cash.count());
+ // test minus
+ cash = new Cash(8);
+ assertTrue(cash.minus(5));
+ assertEquals(3, cash.count());
+ assertFalse(cash.minus(6));
+ assertEquals(3, cash.count());
+ // test update
+ cash.plus(5);
+ assertTrue(cash.minus(5));
+ assertEquals(3, cash.count());
+ }
+}
diff --git a/assets/banner-wide-black.svg b/assets/banner-wide-black.svg
new file mode 100644
index 000000000000..221a3b929040
--- /dev/null
+++ b/assets/banner-wide-black.svg
@@ -0,0 +1,39 @@
+
+
+
+
diff --git a/assets/banner-wide-white.svg b/assets/banner-wide-white.svg
new file mode 100644
index 000000000000..fedaf3674506
--- /dev/null
+++ b/assets/banner-wide-white.svg
@@ -0,0 +1,39 @@
+
+
+
+
diff --git a/assets/banner-wide.svg b/assets/banner-wide.svg
new file mode 100644
index 000000000000..f6be64c41514
--- /dev/null
+++ b/assets/banner-wide.svg
@@ -0,0 +1,85 @@
+
+
+
+
diff --git a/async-method-invocation/README.md b/async-method-invocation/README.md
index 2d99820c5d82..519152e1268c 100644
--- a/async-method-invocation/README.md
+++ b/async-method-invocation/README.md
@@ -1,33 +1,217 @@
---
-layout: pattern
-title: Async Method Invocation
-folder: async-method-invocation
-permalink: /patterns/async-method-invocation/
-categories: Concurrency
-tags:
- - Java
- - Difficulty-Intermediate
- - Functional
- - Reactive
+title: "Async Method Invocation Pattern in Java: Elevate Performance with Asynchronous Programming"
+shortTitle: Async Method Invocation
+description: "Learn about the Async Method Invocation pattern in Java for asynchronous method calls, enhancing concurrency, scalability, and responsiveness in your applications. Explore real-world examples and code implementations."
+category: Concurrency
+language: en
+tag:
+ - Asynchronous
+ - Decoupling
+ - Reactive
+ - Scalability
+ - Thread management
---
-## Intent
-Asynchronous method invocation is pattern where the calling thread
-is not blocked while waiting results of tasks. The pattern provides parallel
-processing of multiple independent tasks and retrieving the results via
-callbacks or waiting until everything is done.
+## Also known as
-
+* Asynchronous Procedure Call
-## Applicability
-Use async method invocation pattern when
+## Intent of Async Method Invocation Design Pattern
-* you have multiple independent tasks that can run in parallel
-* you need to improve the performance of a group of sequential tasks
-* you have limited amount of processing capacity or long running tasks and the
- caller should not wait the tasks to be ready
+The Async Method Invocation pattern is designed to enhance concurrency by allowing methods to be called asynchronously. This pattern helps in executing parallel tasks, reducing wait times, and improving system throughput.
-## Real world examples
+## Detailed Explanation of Async Method Invocation Pattern with Real-World Examples
-* [FutureTask](http://docs.oracle.com/javase/8/docs/api/java/util/concurrent/FutureTask.html), [CompletableFuture](https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/CompletableFuture.html) and [ExecutorService](http://docs.oracle.com/javase/8/docs/api/java/util/concurrent/ExecutorService.html) (Java)
-* [Task-based Asynchronous Pattern](https://msdn.microsoft.com/en-us/library/hh873175.aspx) (.NET)
+Real-world example
+
+> Asynchronous method invocation enables non-blocking operations, allowing multiple processes to run concurrently. This pattern is particularly useful in applications requiring high scalability and performance, such as web servers and microservices.
+>
+> In the context of space rockets, an analogous example of the Async Method Invocation pattern can be seen in the communication between the mission control center and the onboard systems of the rocket. When mission control sends a command to the rocket to adjust its trajectory or perform a system check, they do not wait idly for the rocket to complete the task and report back. Instead, mission control continues to monitor other aspects of the mission and manage different tasks. The rocket executes the command asynchronously and sends a status update or result back to mission control once the operation is complete. This allows mission control to efficiently manage multiple concurrent operations without being blocked by any single task, similar to how asynchronous method invocation works in software systems.
+
+In plain words
+
+> Asynchronous method invocation starts task processing and returns immediately before the task is ready. The results of the task processing are returned to the caller later.
+
+Wikipedia says
+
+> In multithreaded computer programming, asynchronous method invocation (AMI), also known as asynchronous method calls or the asynchronous pattern is a design pattern in which the call site is not blocked while waiting for the called code to finish. Instead, the calling thread is notified when the reply arrives. Polling for a reply is an undesired option.
+
+Sequence diagram
+
+
+
+## Programmatic Example of Async Method Invocation Pattern in Java
+
+Consider a scenario where multiple tasks need to be executed simultaneously. Using the Async Method Invocation pattern, you can initiate these tasks without waiting for each to complete, thus optimizing resource usage and reducing latency.
+
+In this example, we are launching space rockets and deploying lunar rovers.
+
+The application demonstrates the async method invocation pattern. The key parts of the pattern are`AsyncResult` which is an intermediate container for an asynchronously evaluated value, `AsyncCallback` which can be provided to be executed on task completion and `AsyncExecutor` that manages the execution of the async tasks.
+
+```java
+public interface AsyncResult
- * The main method shows example flow of async invocations. The main thread starts multiple tasks with variable
- * durations and then continues its own work. When the main thread has done it's job it collects the results of the
- * async tasks. Two of the tasks are handled with callbacks, meaning the callbacks are executed immediately when the
- * tasks complete.
- *
- * Noteworthy difference of thread usage between the async results and callbacks is that the async results are collected
- * in the main thread but the callbacks are executed within the worker threads. This should be noted when working with
- * thread pools.
- *
- * Java provides its own implementations of async method invocation pattern. FutureTask, CompletableFuture and
- * ExecutorService are the real world implementations of this pattern. But due to the nature of parallel programming,
- * the implementations are not trivial. This example does not take all possible scenarios into account but rather
- * provides a simple version that helps to understand the pattern.
+ * In this example, we are launching space rockets and deploying lunar rovers.
+ *
+ * The application demonstrates the async method invocation pattern. The key parts of the pattern
+ * are The main method shows example flow of async invocations. The main thread starts multiple tasks
+ * with variable durations and then continues its own work. When the main thread has done it's job
+ * it collects the results of the async tasks. Two of the tasks are handled with callbacks, meaning
+ * the callbacks are executed immediately when the tasks complete.
+ *
+ * Noteworthy difference of thread usage between the async results and callbacks is that the
+ * async results are collected in the main thread but the callbacks are executed within the worker
+ * threads. This should be noted when working with thread pools.
+ *
+ * Java provides its own implementations of async method invocation pattern. FutureTask,
+ * CompletableFuture and ExecutorService are the real world implementations of this pattern. But due
+ * to the nature of parallel programming, the implementations are not trivial. This example does not
+ * take all possible scenarios into account but rather provides a simple version that helps to
+ * understand the pattern.
*
* @see AsyncResult
* @see AsyncCallback
* @see AsyncExecutor
- *
* @see java.util.concurrent.FutureTask
* @see java.util.concurrent.CompletableFuture
* @see java.util.concurrent.ExecutorService
*/
+@Slf4j
public class App {
- private static final Logger LOGGER = LoggerFactory.getLogger(App.class);
+ private static final String ROCKET_LAUNCH_LOG_PATTERN = "Space rocket <%s> launched successfully";
- /**
- * Program entry point
- */
+ /** Program entry point. */
public static void main(String[] args) throws Exception {
// construct a new executor that will run async tasks
- AsyncExecutor executor = new ThreadAsyncExecutor();
+ var executor = new ThreadAsyncExecutor();
// start few async tasks with varying processing times, two last with callback handlers
- AsyncResult Solution: Inserted assertion to check whether the execution of the main method in {@link
+ * App} throws an exception.
+ */
@Test
- public void test() throws Exception {
- String[] args = {};
- App.main(args);
+ void shouldExecuteApplicationWithoutException() {
+
+ assertDoesNotThrow(() -> App.main(new String[] {}));
}
}
diff --git a/async-method-invocation/src/test/java/com/iluwatar/async/method/invocation/ThreadAsyncExecutorTest.java b/async-method-invocation/src/test/java/com/iluwatar/async/method/invocation/ThreadAsyncExecutorTest.java
index b5c4fff674de..d6540ce77309 100644
--- a/async-method-invocation/src/test/java/com/iluwatar/async/method/invocation/ThreadAsyncExecutorTest.java
+++ b/async-method-invocation/src/test/java/com/iluwatar/async/method/invocation/ThreadAsyncExecutorTest.java
@@ -1,6 +1,8 @@
-/**
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
* The MIT License
- * Copyright (c) 2014-2016 Ilkka Seppälä
+ * Copyright © 2014-2022 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
@@ -22,322 +24,326 @@
*/
package com.iluwatar.async.method.invocation;
-import org.junit.jupiter.api.Test;
-import org.mockito.ArgumentCaptor;
-import org.mockito.Matchers;
-
-import java.util.Optional;
-import java.util.concurrent.Callable;
-import java.util.concurrent.ExecutionException;
-
import static java.time.Duration.ofMillis;
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertFalse;
-import static org.junit.jupiter.api.Assertions.assertNotNull;
-import static org.junit.jupiter.api.Assertions.assertSame;
-import static org.junit.jupiter.api.Assertions.assertTimeout;
-import static org.junit.jupiter.api.Assertions.assertTrue;
-import static org.junit.jupiter.api.Assertions.fail;
-import static org.mockito.Matchers.eq;
-import static org.mockito.Mockito.mock;
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.ArgumentMatchers.*;
import static org.mockito.Mockito.timeout;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.verifyNoMoreInteractions;
-import static org.mockito.Mockito.verifyZeroInteractions;
import static org.mockito.Mockito.when;
import static org.mockito.internal.verification.VerificationModeFactory.times;
-/**
- * Date: 12/6/15 - 10:49 AM
- *
- * @author Jeroen Meulemeester
- */
-public class ThreadAsyncExecutorTest {
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutionException;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.mockito.ArgumentCaptor;
+import org.mockito.Captor;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
- /**
- * Test used to verify the happy path of {@link ThreadAsyncExecutor#startProcess(Callable)}
- */
+/** ThreadAsyncExecutorTest */
+class ThreadAsyncExecutorTest {
+
+ @Captor private ArgumentCaptor
+ *
* Pirates are coming! we need a {@link RowingBoat} to flee! We have a {@link FishingBoat} and our
* captain. We have no time to make up a new ship! we need to reuse this {@link FishingBoat}. The
- * captain needs a rowing boat which he can operate. The spec is in {@link RowingBoat}. We will
- * use the Adapter pattern to reuse {@link FishingBoat}.
- *
+ * captain needs a rowing boat which he can operate. The spec is in {@link RowingBoat}. We will use
+ * the Adapter pattern to reuse {@link FishingBoat}.
*/
-public class App {
+public final class App {
+
+ private App() {}
/**
* Program entry point.
*
* @param args command line args
*/
- public static void main(String[] args) {
- // The captain can only operate rowing boats but with adapter he is able to use fishing boats as well
- Captain captain = new Captain(new FishingBoatAdapter());
+ public static void main(final String[] args) {
+ // The captain can only operate rowing boats but with adapter he is able to
+ // use fishing boats as well
+ var captain = new Captain(new FishingBoatAdapter());
captain.row();
}
}
diff --git a/adapter/src/main/java/com/iluwatar/adapter/Captain.java b/adapter/src/main/java/com/iluwatar/adapter/Captain.java
index 8593ca321975..3b771e9d833e 100644
--- a/adapter/src/main/java/com/iluwatar/adapter/Captain.java
+++ b/adapter/src/main/java/com/iluwatar/adapter/Captain.java
@@ -1,6 +1,8 @@
-/**
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
* The MIT License
- * Copyright (c) 2014-2016 Ilkka Seppälä
+ * Copyright © 2014-2022 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
@@ -22,26 +24,22 @@
*/
package com.iluwatar.adapter;
+import lombok.AllArgsConstructor;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+
/**
* The Captain uses {@link RowingBoat} to sail.
* This is the client in the pattern.
*/
-public class Captain {
+@Setter
+@NoArgsConstructor
+@AllArgsConstructor
+public final class Captain {
private RowingBoat rowingBoat;
- public Captain() {}
-
- public Captain(RowingBoat rowingBoat) {
- this.rowingBoat = rowingBoat;
- }
-
- public void setRowingBoat(RowingBoat rowingBoat) {
- this.rowingBoat = rowingBoat;
- }
-
- public void row() {
+ void row() {
rowingBoat.row();
}
-
}
diff --git a/adapter/src/main/java/com/iluwatar/adapter/FishingBoat.java b/adapter/src/main/java/com/iluwatar/adapter/FishingBoat.java
index c46814d18f16..dd39f88f1ce0 100644
--- a/adapter/src/main/java/com/iluwatar/adapter/FishingBoat.java
+++ b/adapter/src/main/java/com/iluwatar/adapter/FishingBoat.java
@@ -1,6 +1,8 @@
-/**
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
* The MIT License
- * Copyright (c) 2014-2016 Ilkka Seppälä
+ * Copyright © 2014-2022 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
@@ -22,21 +24,16 @@
*/
package com.iluwatar.adapter;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
+import lombok.extern.slf4j.Slf4j;
/**
- *
- * Device class (adaptee in the pattern). We want to reuse this class.
- * Fishing boat moves by sailing.
- *
+ * Device class (adaptee in the pattern). We want to reuse this class. Fishing boat moves by
+ * sailing.
*/
-public class FishingBoat {
-
- private static final Logger LOGGER = LoggerFactory.getLogger(FishingBoat.class);
+@Slf4j
+final class FishingBoat {
- public void sail() {
+ void sail() {
LOGGER.info("The fishing boat is sailing");
}
-
}
diff --git a/adapter/src/main/java/com/iluwatar/adapter/FishingBoatAdapter.java b/adapter/src/main/java/com/iluwatar/adapter/FishingBoatAdapter.java
index 1e758e917040..8c7e9e88e220 100644
--- a/adapter/src/main/java/com/iluwatar/adapter/FishingBoatAdapter.java
+++ b/adapter/src/main/java/com/iluwatar/adapter/FishingBoatAdapter.java
@@ -1,6 +1,8 @@
-/**
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
* The MIT License
- * Copyright (c) 2014-2016 Ilkka Seppälä
+ * Copyright © 2014-2022 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
@@ -23,21 +25,14 @@
package com.iluwatar.adapter;
/**
- *
* Adapter class. Adapts the interface of the device ({@link FishingBoat}) into {@link RowingBoat}
* interface expected by the client ({@link Captain}).
- *
*/
public class FishingBoatAdapter implements RowingBoat {
- private FishingBoat boat;
-
- public FishingBoatAdapter() {
- boat = new FishingBoat();
- }
+ private final FishingBoat boat = new FishingBoat();
- @Override
- public void row() {
+ public final void row() {
boat.sail();
}
}
diff --git a/adapter/src/main/java/com/iluwatar/adapter/RowingBoat.java b/adapter/src/main/java/com/iluwatar/adapter/RowingBoat.java
index a9ca9ad39717..55eeeaf4bd42 100644
--- a/adapter/src/main/java/com/iluwatar/adapter/RowingBoat.java
+++ b/adapter/src/main/java/com/iluwatar/adapter/RowingBoat.java
@@ -1,6 +1,8 @@
-/**
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
* The MIT License
- * Copyright (c) 2014-2016 Ilkka Seppälä
+ * Copyright © 2014-2022 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
@@ -25,10 +27,8 @@
/**
* The interface expected by the client.
* A rowing boat is rowed to move.
- *
*/
public interface RowingBoat {
void row();
-
}
diff --git a/adapter/src/main/java/com/iluwatar/adapter/package-info.java b/adapter/src/main/java/com/iluwatar/adapter/package-info.java
new file mode 100644
index 000000000000..c42f2ac86ceb
--- /dev/null
+++ b/adapter/src/main/java/com/iluwatar/adapter/package-info.java
@@ -0,0 +1,25 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.adapter;
diff --git a/adapter/src/test/java/com/iluwatar/adapter/AdapterPatternTest.java b/adapter/src/test/java/com/iluwatar/adapter/AdapterPatternTest.java
index 82a951e30bdc..bc4984da3d6f 100644
--- a/adapter/src/test/java/com/iluwatar/adapter/AdapterPatternTest.java
+++ b/adapter/src/test/java/com/iluwatar/adapter/AdapterPatternTest.java
@@ -1,6 +1,8 @@
-/**
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
* The MIT License
- * Copyright (c) 2014-2016 Ilkka Seppälä
+ * Copyright © 2014-2022 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
@@ -22,20 +24,16 @@
*/
package com.iluwatar.adapter;
-import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Test;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.verify;
import java.util.HashMap;
import java.util.Map;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
-import static org.mockito.Mockito.spy;
-import static org.mockito.Mockito.verify;
-
-/**
- * Test class
- *
- */
-public class AdapterPatternTest {
+/** Tests for the adapter pattern. */
+class AdapterPatternTest {
private MapAsyncResult which is an intermediate container for an asynchronously evaluated value,
- * AsyncCallback which can be provided to be executed on task completion and AsyncExecutor
- * that manages the execution of the async tasks.
- * AsyncResult which is an intermediate container for an asynchronously evaluated
+ * value, AsyncCallback which can be provided to be executed on task completion and
+ * AsyncExecutor that manages the execution of the async tasks.
+ *
+ *