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notes/设计模式.md

@@ -1033,7 +1033,162 @@ public class Client {
 
 ### 意图
 
-使用中间人对象来封装对象之间的交互。中间人模式可以降低交互对象之间的耦合程度。
+集中相关对象之间复杂的沟通和控制方式。
+
+### 类图
+
+- Mediator：中介者，定义一个接口用于与各同事（Colleague）对象通信。
+- Colleague：同事，相关对象
+
+<div align="center"> <img src="../pics//d0afdd23-c9a5-4d1c-9b3d-404bff3bd0d1.png"/> </div><br>
+
+### 实现
+
+Alarm（闹钟）、CoffeePot（咖啡壶）、Calendar（日历）、Sprinkler（喷头）是一组相关的对象，在某个对象的事件产生时需要去操作其它对象，形成了下面这种依赖结构：
+
+<div align="center"> <img src="../pics//82cfda3b-b53b-4c89-9fdb-26dd2db0cd02.jpg"/> </div><br>
+
+使用中介者模式可以将复杂的依赖结构变成星形结构：
+
+<div align="center"> <img src="../pics//5359cbf5-5a79-4874-9b17-f23c53c2cb80.jpg"/> </div><br>
+
+```java
+public abstract class Colleague {
+    public abstract void onEvent(Mediator mediator);
+}
+```
+
+```java
+public class Alarm extends Colleague {
+
+    @Override
+    public void onEvent(Mediator mediator) {
+        mediator.doEvent("alarm");
+    }
+
+    public void doAlarm() {
+        System.out.println("doAlarm()");
+    }
+}
+```
+
+```java
+public class CoffeePot extends Colleague {
+    @Override
+    public void onEvent(Mediator mediator) {
+        mediator.doEvent("coffeePot");
+    }
+
+    public void doCoffeePot() {
+        System.out.println("doCoffeePot()");
+    }
+}
+```
+
+```java
+public class Calender extends Colleague {
+    @Override
+    public void onEvent(Mediator mediator) {
+        mediator.doEvent("calender");
+    }
+
+    public void doCalender() {
+        System.out.println("doCalender()");
+    }
+}
+```
+
+```java
+public class Sprinkler extends Colleague {
+    @Override
+    public void onEvent(Mediator mediator) {
+        mediator.doEvent("sprinkler");
+    }
+
+    public void doSprinkler() {
+        System.out.println("doSprinkler()");
+    }
+}
+```
+
+```java
+public abstract class Mediator {
+    public abstract void doEvent(String eventType);
+}
+```
+
+```java
+public class ConcreteMediator extends Mediator {
+    private Alarm alarm;
+    private CoffeePot coffeePot;
+    private Calender calender;
+    private Sprinkler sprinkler;
+
+    public ConcreteMediator(Alarm alarm, CoffeePot coffeePot, Calender calender, Sprinkler sprinkler) {
+        this.alarm = alarm;
+        this.coffeePot = coffeePot;
+        this.calender = calender;
+        this.sprinkler = sprinkler;
+    }
+
+    @Override
+    public void doEvent(String eventType) {
+        switch (eventType) {
+            case "alarm":
+                doAlarmEvent();
+                break;
+            case "coffeePot":
+                doCoffeePotEvent();
+                break;
+            case "calender":
+                doCalenderEvent();
+                break;
+            default:
+                doSprinklerEvent();
+        }
+    }
+
+    public void doAlarmEvent() {
+        alarm.doAlarm();
+        coffeePot.doCoffeePot();
+        calender.doCalender();
+        sprinkler.doSprinkler();
+    }
+
+    public void doCoffeePotEvent() {
+        // ...
+    }
+
+    public void doCalenderEvent() {
+        // ...
+    }
+
+    public void doSprinklerEvent() {
+        // ...
+    }
+}
+```
+
+```java
+public class Client {
+    public static void main(String[] args) {
+        Alarm alarm = new Alarm();
+        CoffeePot coffeePot = new CoffeePot();
+        Calender calender = new Calender();
+        Sprinkler sprinkler = new Sprinkler();
+        Mediator mediator = new ConcreteMediator(alarm, coffeePot, calender, sprinkler);
+        // 闹钟事件到达，调用中介者就可以操作相关对象
+        alarm.onEvent(mediator);
+    }
+}
+```
+
+```java
+doAlarm()
+doCoffeePot()
+doCalender()
+doSprinkler()
+```
 
 ### JDK