docs: update .all-contributorsrc [skip ci]

* #1310 Implemented registry pattern

* fixed parent pom version

* added empty line in registry.urm.puml

Co-authored-by: Subhrodip Mohanta <subhrodipmohanta@gmail.com>

.all-contributorsrc

@@ -1296,6 +1296,33 @@
       "contributions": [
         "doc"
       ]
+    },
+    {
+      "login": "omk13",
+      "name": "Omar Karazoun",
+      "avatar_url": "https://avatars0.githubusercontent.com/u/59054172?v=4",
+      "profile": "https://github.com/omk13",
+      "contributions": [
+        "code"
+      ]
+    },
+    {
+      "login": "jeff303",
+      "name": "Jeff Evans",
+      "avatar_url": "https://avatars0.githubusercontent.com/u/3521562?v=4",
+      "profile": "https://github.com/jeff303",
+      "contributions": [
+        "code"
+      ]
+    },
+    {
+      "login": "viveksb007",
+      "name": "Vivek Singh",
+      "avatar_url": "https://avatars1.githubusercontent.com/u/12713808?v=4",
+      "profile": "https://viveksb007.github.io",
+      "contributions": [
+        "code"
+      ]
     }
   ],
   "contributorsPerLine": 4,

README.md

@@ -10,7 +10,7 @@
 [![Coverage](https://sonarcloud.io/api/project_badges/measure?project=iluwatar_java-design-patterns&metric=coverage)](https://sonarcloud.io/dashboard?id=iluwatar_java-design-patterns)
 [![Join the chat at https://gitter.im/iluwatar/java-design-patterns](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/iluwatar/java-design-patterns?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-142-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-145-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 # Introduction
@@ -282,6 +282,11 @@ This project is licensed under the terms of the MIT license.
   <tr>
     <td align="center"><a href="https://ibrahimalii.github.io/"><img src="https://avatars2.githubusercontent.com/u/21141301?v=4" width="100px;" alt=""/><br /><sub><b>Ibrahim ali abdelghany</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/pulls?q=is%3Apr+reviewed-by%3AibrahimAlii" title="Reviewed Pull Requests">👀</a></td>
     <td align="center"><a href="https://github.com/gkulkarni2020"><img src="https://avatars3.githubusercontent.com/u/5161548?v=4" width="100px;" alt=""/><br /><sub><b>Girish Kulkarni</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=gkulkarni2020" title="Documentation">📖</a></td>
+    <td align="center"><a href="https://github.com/omk13"><img src="https://avatars0.githubusercontent.com/u/59054172?v=4" width="100px;" alt=""/><br /><sub><b>Omar Karazoun</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=omk13" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/jeff303"><img src="https://avatars0.githubusercontent.com/u/3521562?v=4" width="100px;" alt=""/><br /><sub><b>Jeff Evans</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=jeff303" title="Code">💻</a></td>
+  </tr>
+  <tr>
+    <td align="center"><a href="https://viveksb007.github.io"><img src="https://avatars1.githubusercontent.com/u/12713808?v=4" width="100px;" alt=""/><br /><sub><b>Vivek Singh</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=viveksb007" title="Code">💻</a></td>
   </tr>
 </table>
 

factory/README.md

@@ -98,7 +98,7 @@ Now on the client code we can create different types of cars using the factory c
 var car1 = CarsFactory.getCar(CarType.FORD);
 var car2 = CarsFactory.getCar(CarType.FERRARI);
 LOGGER.info(car1.getDescription());
-LOGGER.info(car2.getDescription());;
+LOGGER.info(car2.getDescription());
 ```
 
 Program output:

game-loop/src/test/java/com/iluwatar/gameloop/AppTest.java

@@ -23,7 +23,7 @@
 
 package com.iluwatar.gameloop;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 
 import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 

game-loop/src/test/java/com/iluwatar/gameloop/FixedStepGameLoopTest.java

@@ -23,10 +23,11 @@
 
 package com.iluwatar.gameloop;
 
-import org.junit.After;
+import static org.junit.jupiter.api.Assertions.assertEquals;
-import org.junit.Assert;
+
-import org.junit.Before;
+import org.junit.jupiter.api.Test;
-import org.junit.Test;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
 
 /**
  * FixedStepGameLoop unit test class.
@@ -35,12 +36,12 @@ public class FixedStepGameLoopTest {
 
   private FixedStepGameLoop gameLoop;
 
-  @Before
+  @BeforeEach
   public void setup() {
     gameLoop = new FixedStepGameLoop();
   }
 
-  @After
+  @AfterEach
   public void tearDown() {
     gameLoop = null;
   }
@@ -48,7 +49,7 @@ public class FixedStepGameLoopTest {
   @Test
   public void testUpdate() {
     gameLoop.update();
-    Assert.assertEquals(0.01f, gameLoop.controller.getBulletPosition(), 0);
+    assertEquals(0.01f, gameLoop.controller.getBulletPosition(), 0);
   }
 
 }

game-loop/src/test/java/com/iluwatar/gameloop/FrameBasedGameLoopTest.java

@@ -23,10 +23,10 @@
 
 package com.iluwatar.gameloop;
 
-import org.junit.After;
+import static org.junit.jupiter.api.Assertions.assertEquals;
-import org.junit.Assert;
+
-import org.junit.Before;
+import org.junit.jupiter.api.AfterEach;
-import org.junit.Test;
+import org.junit.jupiter.api.BeforeEach;
 
 /**
  * FrameBasedGameLoop unit test class.
@@ -35,19 +35,19 @@ public class FrameBasedGameLoopTest {
 
   private FrameBasedGameLoop gameLoop;
 
-  @Before
+  @BeforeEach
   public void setup() {
     gameLoop = new FrameBasedGameLoop();
   }
 
-  @After
+  @AfterEach
   public void tearDown() {
     gameLoop = null;
   }
 
-  @Test
+  @org.junit.jupiter.api.Test
   public void testUpdate() {
     gameLoop.update();
-    Assert.assertEquals(0.5f, gameLoop.controller.getBulletPosition(), 0);
+    assertEquals(0.5f, gameLoop.controller.getBulletPosition(), 0);
   }
 }

game-loop/src/test/java/com/iluwatar/gameloop/GameControllerTest.java

@@ -23,34 +23,33 @@
 
 package com.iluwatar.gameloop;
 
-import org.junit.After;
+import org.junit.jupiter.api.Assertions;
-import org.junit.Assert;
+import org.junit.jupiter.api.AfterEach;
-import org.junit.Before;
+import org.junit.jupiter.api.BeforeEach;
-import org.junit.Test;
 
 public class GameControllerTest {
 
   private GameController controller;
 
-  @Before
+  @BeforeEach
   public void setup() {
     controller = new GameController();
   }
 
-  @After
+  @AfterEach
   public void tearDown() {
     controller = null;
   }
 
-  @Test
+  @org.junit.jupiter.api.Test
   public void testMoveBullet() {
     controller.moveBullet(1.5f);
-    Assert.assertEquals(1.5f, controller.bullet.getPosition(), 0);
+    Assertions.assertEquals(1.5f, controller.bullet.getPosition(), 0);
   }
 
-  @Test
+  @org.junit.jupiter.api.Test
   public void testGetBulletPosition() {
-    Assert.assertEquals(controller.bullet.getPosition(), controller.getBulletPosition(), 0);
+    Assertions.assertEquals(controller.bullet.getPosition(), controller.getBulletPosition(), 0);
   }
 
 }

game-loop/src/test/java/com/iluwatar/gameloop/GameLoopTest.java

@@ -23,10 +23,9 @@
 
 package com.iluwatar.gameloop;
 
-import org.junit.After;
+import org.junit.jupiter.api.AfterEach;
-import org.junit.Assert;
+import org.junit.jupiter.api.Assertions;
-import org.junit.Before;
+import org.junit.jupiter.api.BeforeEach;
-import org.junit.Test;
 
 /**
  * GameLoop unit test class.
@@ -38,7 +37,7 @@ public class GameLoopTest {
   /**
    * Create mock implementation of GameLoop.
    */
-  @Before
+  @BeforeEach
   public void setup() {
     gameLoop = new GameLoop() {
       @Override
@@ -46,26 +45,26 @@ public class GameLoopTest {
     };
   }
 
-  @After
+  @AfterEach
   public void tearDown() {
     gameLoop = null;
   }
 
-  @Test
+  @org.junit.jupiter.api.Test
   public void testRun() {
     gameLoop.run();
-    Assert.assertEquals(GameStatus.RUNNING, gameLoop.status);
+    Assertions.assertEquals(GameStatus.RUNNING, gameLoop.status);
   }
 
-  @Test
+  @org.junit.jupiter.api.Test
   public void testStop() {
     gameLoop.stop();
-    Assert.assertEquals(GameStatus.STOPPED, gameLoop.status);
+    Assertions.assertEquals(GameStatus.STOPPED, gameLoop.status);
   }
 
-  @Test
+  @org.junit.jupiter.api.Test
   public void testIsGameRunning() {
-    Assert.assertFalse(gameLoop.isGameRunning());
+    Assertions.assertFalse(gameLoop.isGameRunning());
   }
 
 }

game-loop/src/test/java/com/iluwatar/gameloop/VariableStepGameLoopTest.java

@@ -23,11 +23,9 @@
 
 package com.iluwatar.gameloop;
 
-import java.lang.reflect.InvocationTargetException;
+import org.junit.jupiter.api.Assertions;
-import org.junit.After;
+import org.junit.jupiter.api.AfterEach;
-import org.junit.Assert;
+import org.junit.jupiter.api.BeforeEach;
-import org.junit.Before;
-import org.junit.Test;
 
 /**
  * VariableStepGameLoop unit test class.
@@ -36,19 +34,19 @@ public class VariableStepGameLoopTest {
 
   private VariableStepGameLoop gameLoop;
 
-  @Before
+  @BeforeEach
   public void setup() {
     gameLoop = new VariableStepGameLoop();
   }
 
-  @After
+  @AfterEach
   public void tearDown() {
     gameLoop = null;
   }
 
-  @Test
+  @org.junit.jupiter.api.Test
   public void testUpdate() {
     gameLoop.update(20L);
-    Assert.assertEquals(0.01f, gameLoop.controller.getBulletPosition(), 0);
+    Assertions.assertEquals(0.01f, gameLoop.controller.getBulletPosition(), 0);
   }
 }

pom.xml

@@ -195,6 +195,7 @@
         <module>strangler</module>
         <module>arrange-act-assert</module>
         <module>transaction-script</module>
+        <module>registry</module>
         <module>filterer</module>
         <module>factory</module>
         <module>separated-interface</module>

registry/README.md

@@ -0,0 +1,86 @@
+---
+layout: pattern
+title: Registry
+folder: registry
+permalink: /patterns/registry/
+categories: Creational
+tags:
+ - Instantiation
+---
+
+## Intent
+Stores the objects of a single class and provide a global point of access to them. 
+Similar to Multiton pattern, only difference is that in a registry there is no restriction on the number of objects.
+
+## Explanation
+
+In Plain Words
+
+> Registry is a well-known object that other objects can use to find common objects and services.
+
+**Programmatic Example**
+Below is a `Customer` Class
+
+```java
+public class Customer {
+
+  private final String id;
+  private final String name;
+
+  public Customer(String id, String name) {
+    this.id = id;
+    this.name = name;
+  }
+
+  public String getId() {
+    return id;
+  }
+
+  public String getName() {
+    return name;
+  }
+
+}
+```
+
+This registry of the `Customer` objects is `CustomerRegistry`
+```java
+public final class CustomerRegistry {
+
+  private static final CustomerRegistry instance = new CustomerRegistry();
+
+  public static CustomerRegistry getInstance() {
+    return instance;
+  }
+
+  private final Map<String, Customer> customerMap;
+
+  private CustomerRegistry() {
+    customerMap = new ConcurrentHashMap<>();
+  }
+
+  public Customer addCustomer(Customer customer) {
+    return customerMap.put(customer.getId(), customer);
+  }
+
+  public Customer getCustomer(String id) {
+    return customerMap.get(id);
+  }
+
+}
+```
+
+## Class diagram
+![Registry](./etc/registry.png)
+
+## Applicability
+Use Registry pattern when 
+
+* client wants reference of some object, so client can lookup for that object in the object's registry.
+
+## Consequences
+Large number of bulky objects added to registry would result in a lot of memory consumption as objects in the registry are not garbage collected.
+
+## Credits
+* https://www.martinfowler.com/eaaCatalog/registry.html
+* https://wiki.c2.com/?RegistryPattern

registry/etc/registry.urm.puml

@@ -0,0 +1,21 @@
+@startuml
+package com.iluwatar.registry {
+  class App {
+    - LOGGER : Logger {static}
+    + App()
+    + main(args : String[]) {static}
+  }
+  class Customer {
+    - id : String
+    - name : String
+    + getId() : String
+    + getName() : String
+    + toString() : String
+  }
+  class CustomerRegistry {
+    + addCustomer(customer : Customer)
+    + getCustomer(id : String)
+  }
+}
+Customer --> "-addCustomer" CustomerRegistry
+@enduml

registry/pom.xml

@@ -0,0 +1,46 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+
+  <parent>
+    <groupId>com.iluwatar</groupId>
+    <artifactId>java-design-patterns</artifactId>
+    <version>1.24.0-SNAPSHOT</version>
+  </parent>
+  <artifactId>registry</artifactId>
+
+  <dependencies>
+    <dependency>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter-engine</artifactId>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+    </dependency>
+  </dependencies>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-assembly-plugin</artifactId>
+        <executions>
+          <execution>
+            <configuration>
+              <archive>
+                <manifest>
+                  <mainClass>com.iluwatar.registry.App</mainClass>
+                </manifest>
+              </archive>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+
+</project>

registry/src/main/java/com/iluwatar/registry/App.java

@@ -0,0 +1,27 @@
+package com.iluwatar.registry;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class App {
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(App.class);
+
+  /**
+   * Program entry point.
+   *
+   * @param args command line args
+   */
+  public static void main(String[] args) {
+    CustomerRegistry customerRegistry = CustomerRegistry.getInstance();
+    var john = new Customer("1", "John");
+    customerRegistry.addCustomer(john);
+
+    var julia = new Customer("2", "Julia");
+    customerRegistry.addCustomer(julia);
+
+    LOGGER.info("John {}", customerRegistry.getCustomer("1"));
+    LOGGER.info("Julia {}", customerRegistry.getCustomer("2"));
+  }
+
+}

registry/src/main/java/com/iluwatar/registry/Customer.java

@@ -0,0 +1,28 @@
+package com.iluwatar.registry;
+
+public class Customer {
+
+  private final String id;
+  private final String name;
+
+  public Customer(String id, String name) {
+    this.id = id;
+    this.name = name;
+  }
+
+  public String getId() {
+    return id;
+  }
+
+  public String getName() {
+    return name;
+  }
+
+  @Override
+  public String toString() {
+    return "Customer{"
+        + "id='" + id + '\''
+        + ", name='" + name + '\''
+        + '}';
+  }
+}

registry/src/main/java/com/iluwatar/registry/CustomerRegistry.java

@@ -0,0 +1,28 @@
+package com.iluwatar.registry;
+
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+public final class CustomerRegistry {
+
+  private static final CustomerRegistry instance = new CustomerRegistry();
+
+  public static CustomerRegistry getInstance() {
+    return instance;
+  }
+
+  private final Map<String, Customer> customerMap;
+
+  private CustomerRegistry() {
+    customerMap = new ConcurrentHashMap<>();
+  }
+
+  public Customer addCustomer(Customer customer) {
+    return customerMap.put(customer.getId(), customer);
+  }
+
+  public Customer getCustomer(String id) {
+    return customerMap.get(id);
+  }
+
+}

registry/src/test/java/com/iluwatar/registry/CustomerRegistryTest.java

@@ -0,0 +1,44 @@
+package com.iluwatar.registry;
+
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+public class CustomerRegistryTest {
+
+  private static CustomerRegistry customerRegistry;
+
+  @BeforeAll
+  public static void setUp() {
+    customerRegistry = CustomerRegistry.getInstance();
+  }
+
+  @Test
+  public void shouldBeAbleToAddAndQueryCustomerObjectFromRegistry() {
+    Customer john = new Customer("1", "john");
+    Customer julia = new Customer("2", "julia");
+
+    customerRegistry.addCustomer(john);
+    customerRegistry.addCustomer(julia);
+
+    Customer customerWithId1 = customerRegistry.getCustomer("1");
+    assertNotNull(customerWithId1);
+    assertEquals("1", customerWithId1.getId());
+    assertEquals("john", customerWithId1.getName());
+
+    Customer customerWithId2 = customerRegistry.getCustomer("2");
+    assertNotNull(customerWithId2);
+    assertEquals("2", customerWithId2.getId());
+    assertEquals("julia", customerWithId2.getName());
+  }
+
+  @Test
+  public void shouldReturnNullWhenQueriedCustomerIsNotInRegistry() {
+    Customer customerWithId5 = customerRegistry.getCustomer("5");
+    assertNull(customerWithId5);
+  }
+
+}

zh/bridge/README.md

@@ -0,0 +1,205 @@
+---
+layout: pattern
+title: Bridge
+folder: bridge
+permalink: /patterns/bridge/
+categories: Structural
+tags:
+ - Gang of Four
+---
+
+## 又被称为
+
+手柄/身体模式
+
+## 目的
+
+将抽象与其实现分离，以便二者可以独立变化。
+
+## 解释
+
+真实世界例子
+
+> 考虑一下你拥有一种具有不同附魔的武器，并且应该允许将具有不同附魔的不同武器混合使用。 你会怎么做？ 为每个附魔创建每种武器的多个副本，还是只是创建单独的附魔并根据需要为武器设置它？ 桥接模式使您可以进行第二次操作。
+
+通俗的说
+
+> 桥接模式是一个更推荐组合而不是继承的模式。将实现细节从一个层次结构推送到具有单独层次结构的另一个对象。
+
+维基百科说
+
+> 桥接模式是软件工程中使用的一种设计模式，旨在“将抽象与其实现分离，从而使两者可以独立变化”
+
+**程序示例**
+
+翻译一下上面的武器示例。下面我们有武器的类层级：
+
+```java
+public interface Weapon {
+  void wield();
+  void swing();
+  void unwield();
+  Enchantment getEnchantment();
+}
+
+public class Sword implements Weapon {
+
+  private final Enchantment enchantment;
+
+  public Sword(Enchantment enchantment) {
+    this.enchantment = enchantment;
+  }
+
+  @Override
+  public void wield() {
+    LOGGER.info("The sword is wielded.");
+    enchantment.onActivate();
+  }
+
+  @Override
+  public void swing() {
+    LOGGER.info("The sword is swinged.");
+    enchantment.apply();
+  }
+
+  @Override
+  public void unwield() {
+    LOGGER.info("The sword is unwielded.");
+    enchantment.onDeactivate();
+  }
+
+  @Override
+  public Enchantment getEnchantment() {
+    return enchantment;
+  }
+}
+
+public class Hammer implements Weapon {
+
+  private final Enchantment enchantment;
+
+  public Hammer(Enchantment enchantment) {
+    this.enchantment = enchantment;
+  }
+
+  @Override
+  public void wield() {
+    LOGGER.info("The hammer is wielded.");
+    enchantment.onActivate();
+  }
+
+  @Override
+  public void swing() {
+    LOGGER.info("The hammer is swinged.");
+    enchantment.apply();
+  }
+
+  @Override
+  public void unwield() {
+    LOGGER.info("The hammer is unwielded.");
+    enchantment.onDeactivate();
+  }
+
+  @Override
+  public Enchantment getEnchantment() {
+    return enchantment;
+  }
+}
+```
+
+这里是单独的附魔类结构：
+
+```java
+public interface Enchantment {
+  void onActivate();
+  void apply();
+  void onDeactivate();
+}
+
+public class FlyingEnchantment implements Enchantment {
+
+  @Override
+  public void onActivate() {
+    LOGGER.info("The item begins to glow faintly.");
+  }
+
+  @Override
+  public void apply() {
+    LOGGER.info("The item flies and strikes the enemies finally returning to owner's hand.");
+  }
+
+  @Override
+  public void onDeactivate() {
+    LOGGER.info("The item's glow fades.");
+  }
+}
+
+public class SoulEatingEnchantment implements Enchantment {
+
+  @Override
+  public void onActivate() {
+    LOGGER.info("The item spreads bloodlust.");
+  }
+
+  @Override
+  public void apply() {
+    LOGGER.info("The item eats the soul of enemies.");
+  }
+
+  @Override
+  public void onDeactivate() {
+    LOGGER.info("Bloodlust slowly disappears.");
+  }
+}
+```
+
+这里是两种层次结构的实践：
+
+```java
+var enchantedSword = new Sword(new SoulEatingEnchantment());
+enchantedSword.wield();
+enchantedSword.swing();
+enchantedSword.unwield();
+// The sword is wielded.
+// The item spreads bloodlust.
+// The sword is swinged.
+// The item eats the soul of enemies.
+// The sword is unwielded.
+// Bloodlust slowly disappears.
+
+var hammer = new Hammer(new FlyingEnchantment());
+hammer.wield();
+hammer.swing();
+hammer.unwield();
+// The hammer is wielded.
+// The item begins to glow faintly.
+// The hammer is swinged.
+// The item flies and strikes the enemies finally returning to owner's hand.
+// The hammer is unwielded.
+// The item's glow fades.
+```
+
+
+
+## 类图
+
+![alt text](../../bridge/etc/bridge.urm.png "Bridge class diagram")
+
+## 适用性
+
+使用桥接模式当
+
+* 你想永久性的避免抽象和他的实现之间的绑定。有可能是这种情况，当实现需要被选择或者在运行时切换。
+* 抽象和他们的实现应该能通过写子类来扩展。这种情况下，桥接模式让你可以组合不同的抽象和实现并独立的扩展他们。
+* 对抽象的实现的改动应当不会对客户产生影响；也就是说，他们的代码不必重新编译。
+* 你有种类繁多的类。这样的类层次结构表明需要将一个对象分为两部分。Rumbaugh 使用术语“嵌套归纳”来指代这种类层次结构。
+* 你想在多个对象间分享一种实现（可能使用引用计数），这个事实应该对客户隐藏。一个简单的示例是Coplien的String类，其中多个对象可以共享同一字符串表示形式
+
+## 教程
+
+* [Bridge Pattern Tutorial](https://www.journaldev.com/1491/bridge-design-pattern-java)
+
+## 鸣谢
+
+* [Design Patterns: Elements of Reusable Object-Oriented Software](https://www.amazon.com/gp/product/0201633612/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0201633612&linkCode=as2&tag=javadesignpat-20&linkId=675d49790ce11db99d90bde47f1aeb59)
+* [Head First Design Patterns: A Brain-Friendly Guide](https://www.amazon.com/gp/product/0596007124/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0596007124&linkCode=as2&tag=javadesignpat-20&linkId=6b8b6eea86021af6c8e3cd3fc382cb5b)

zh/decorator/README.md

@@ -33,8 +33,6 @@ tags:
 
 以巨魔的为例。首先我有有一个简单的巨魔，实现了巨魔接口。
 
-程序mple. First of all we have a simple troll implementing the troll interface
-
 ```java
 public interface Troll {
   void attack();

zh/dependency-injection/README.md

@@ -0,0 +1,101 @@
+---
+layout: pattern
+title: Dependency Injection
+folder: dependency-injection
+permalink: /patterns/dependency-injection/
+categories: Creational
+tags:
+ - Decoupling
+---
+
+## 目的
+
+依赖注入是一种软件设计模式，其中一个或多个依赖项（或服务）被注入或通过引用传递到一个依赖对象（或客户端）中，并成为客户端状态的一部分。该模式将客户的依赖关系的创建与其自身的行为分开，这使程序设计可以松散耦合，并遵循控制反转和单一职责原则。
+
+## 解释
+
+真实世界例子
+
+> 老巫师喜欢不时地装满烟斗抽烟。 但是，他不想只依赖一个烟草品牌，而是希望能够互换使用它们。 
+
+通俗的说
+
+> 依赖注入将客户端依赖的创建与其自身行为分开。
+
+维基百科说
+
+> 在软件工程中，依赖注入是一种对象接收其依赖的其他对象的技术。 这些其他对象称为依赖项。
+
+**程序示例**
+
+先介绍一下烟草接口和具体的品牌。
+
+```java
+public abstract class Tobacco {
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(Tobacco.class);
+
+  public void smoke(Wizard wizard) {
+    LOGGER.info("{} smoking {}", wizard.getClass().getSimpleName(),
+        this.getClass().getSimpleName());
+  }
+}
+
+public class SecondBreakfastTobacco extends Tobacco {
+}
+
+public class RivendellTobacco extends Tobacco {
+}
+
+public class OldTobyTobacco extends Tobacco {
+}
+```
+
+下面是老巫师的类的层次结构。
+
+```java
+public interface Wizard {
+
+  void smoke();
+}
+
+public class AdvancedWizard implements Wizard {
+
+  private final Tobacco tobacco;
+
+  public AdvancedWizard(Tobacco tobacco) {
+    this.tobacco = tobacco;
+  }
+
+  @Override
+  public void smoke() {
+    tobacco.smoke(this);
+  }
+}
+```
+
+最后我们可以看到给老巫师任意品牌的烟草是多么的简单。
+
+```java
+    var advancedWizard = new AdvancedWizard(new SecondBreakfastTobacco());
+    advancedWizard.smoke();
+```
+
+## 类图
+
+![alt text](../../dependency-injection/etc/dependency-injection.png "Dependency Injection")
+
+## 适用性
+
+使用依赖注入当：
+
+- 当你需要从对象中移除掉具体的实现内容时
+
+* 使用模拟对象或存根隔离地启用类的单元测试
+
+## 鸣谢
+
+* [Dependency Injection Principles, Practices, and Patterns](https://www.amazon.com/gp/product/161729473X/ref=as_li_qf_asin_il_tl?ie=UTF8&tag=javadesignpat-20&creative=9325&linkCode=as2&creativeASIN=161729473X&linkId=57079257a5c7d33755493802f3b884bd)
+* [Clean Code: A Handbook of Agile Software Craftsmanship](https://www.amazon.com/gp/product/0132350882/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0132350882&linkCode=as2&tag=javadesignpat-20&linkId=2c390d89cc9e61c01b9e7005c7842871)
+* [Java 9 Dependency Injection: Write loosely coupled code with Spring 5 and Guice](https://www.amazon.com/gp/product/1788296257/ref=as_li_tl?ie=UTF8&tag=javadesignpat-20&camp=1789&creative=9325&linkCode=as2&creativeASIN=1788296257&linkId=4e9137a3bf722a8b5b156cce1eec0fc1)
+* [Google Guice Tutorial: Open source Java based dependency injection framework](https://www.amazon.com/gp/product/B083P7DZ8M/ref=as_li_tl?ie=UTF8&tag=javadesignpat-20&camp=1789&creative=9325&linkCode=as2&creativeASIN=B083P7DZ8M&linkId=04f0f902c877921e45215b624a124bfe)