增加了以播放视频为例子的中介者模式的讲解

Author: askrain

src/com/company/mediator/computer/CDDevice.java

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+package com.company.mediator.computer;
+
+
+/**
+ * 光驱同事
+ * CD设备负责读取光盘的数据并将数据提供给主板
+ */
+public class CDDevice extends Colleague {
+
+    private String data;//视频数据
+
+    public CDDevice(Mediator mediator) {
+        super(mediator);
+    }
+
+    /**
+     * 读取视频数据
+     *
+     * @return 视频数据
+     */
+    public String read() {
+        return data;
+    }
+
+    /**
+     * 加载视频数据
+     */
+    public void load() {
+//        实际情况中视频数据与音频诗句都在一个数据流中
+        data = "视频数据,音频数据";
+        mediator.changed(this);
+    }
+}

src/com/company/mediator/computer/CPU.java

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+package com.company.mediator.computer;
+
+/**
+ * CPU同事，负责从主板传递来的音、视频数据的解码
+ */
+public class CPU extends Colleague {
+
+    private String dataVideo, dataSound;//视频和音频数据
+
+    public CPU(Mediator mediator) {
+        super(mediator);
+    }
+
+    /**
+     * 获取视频数据
+     *
+     * @return 视频数据
+     */
+    public String getDataVideo() {
+        return dataVideo;
+    }
+
+    /**
+     * 获取音频数据
+     *
+     * @return 音频数据
+     */
+    public String getDataSound() {
+        return dataSound;
+    }
+
+
+    /**
+     * 解码数据
+     *
+     * @param data 音、视频数据
+     */
+    public void decodeData(String data) {
+
+        //分隔 音、视频数据
+        String[] temp = data.split(",");
+
+        //解析音、视频数据
+        dataVideo = temp[0];
+        dataSound = temp[1];
+
+        mediator.changed(this);
+
+    }
+}

src/com/company/mediator/computer/Client.java

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+package com.company.mediator.computer;
+
+
+/**
+ * 通过客户端来模式电脑播放电影的效果
+ */
+public class Client {
+
+    public static void main(String[] args) {
+
+        //构造主板对象
+        MainBoard mediator = new MainBoard();
+
+        //分别构造各个零部件
+        CDDevice cdDevice = new CDDevice(mediator);
+        CPU cpu = new CPU(mediator);
+        GraphicsCard gc = new GraphicsCard(mediator);
+        SoundCard soundCard = new SoundCard(mediator);
+
+        //将各个零部件安装到主板
+        mediator.setCdDevice(cdDevice);
+        mediator.setCpu(cpu);
+        mediator.setSoundCard(soundCard);
+        mediator.setGraphicsCard(gc);
+
+        //完成后就可以开始放片了
+        cdDevice.load();
+    }
+}

src/com/company/mediator/computer/Colleague.java

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+package com.company.mediator.computer;
+
+
+//抽象同事
+public abstract class Colleague {
+    protected Mediator mediator;//每一个同事都应该知道它的中介者
+
+    public Colleague(Mediator mediator) {
+        this.mediator = mediator;
+    }
+}

src/com/company/mediator/computer/GraphicsCard.java

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+package com.company.mediator.computer;
+
+
+/**
+ * 显卡同事 ：播放视频
+ */
+public class GraphicsCard extends Colleague {
+    public GraphicsCard(Mediator mediator) {
+        super(mediator);
+    }
+
+    /**
+     * 播放视频
+     *
+     * @param data 视频数据
+     */
+    public void videoPlay(String data) {
+        System.out.println("视频：" + data);
+    }
+}

src/com/company/mediator/computer/MainBoard.java

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+package com.company.mediator.computer;
+
+
+/**
+ * 主板中介者
+ */
+public class MainBoard extends Mediator {
+
+    private CDDevice cdDevice;//光驱设备
+    private CPU cpu;// CPU
+    private SoundCard soundCard;//声卡设备
+    private GraphicsCard graphicsCard;//显卡设备
+
+
+    @Override
+    public void changed(Colleague c) {
+//       如果光驱读取了数据
+        if (c == cdDevice) {  //关于此处为什么用 == 而不是instanceOf 是因为在客户端最终调用之前给中介者
+//            设置了同一个光驱 和 cpu,所以比较的内存地址
+            handleCD((CDDevice) c);
+        } else if (c == cpu) {//如果CPU处理完数据
+            handleCPU((CPU) c);
+        }
+    }
+
+    /**
+     * 处理光驱读取数据后与其他设备的交互
+     *
+     * @param cdDevice
+     */
+    private void handleCD(CDDevice cdDevice) {
+        cpu.decodeData(cdDevice.read());
+    }
+
+    /**
+     * 处理cpu读取数据后与其他设备的交互
+     *
+     * @param cpu
+     */
+    private void handleCPU(CPU cpu) {
+        soundCard.soundPlay(cpu.getDataSound());
+        graphicsCard.videoPlay(cpu.getDataVideo());
+    }
+
+
+    /**
+     * 设置CD设备
+     *
+     * @param cdDevice cd设备
+     */
+    public void setCdDevice(CDDevice cdDevice) {
+        this.cdDevice = cdDevice;
+    }
+
+
+    /**
+     * 设置cpu
+     *
+     * @param cpu
+     */
+    public void setCpu(CPU cpu) {
+        this.cpu = cpu;
+    }
+
+
+    /**
+     * 设置声卡
+     *
+     * @param soundCard 声卡设备
+     */
+    public void setSoundCard(SoundCard soundCard) {
+        this.soundCard = soundCard;
+    }
+
+    /**
+     * 设置显卡
+     *
+     * @param graphicsCard 显卡设备
+     */
+    public void setGraphicsCard(GraphicsCard graphicsCard) {
+        this.graphicsCard = graphicsCard;
+    }
+}

src/com/company/mediator/computer/Mediator.java

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+package com.company.mediator.computer;
+
+//抽象中介者
+public abstract class Mediator {
+
+    /**
+     * 同事对象改变时通知中介者的方法
+     * 在同事对象改变时由中介者去通知其他的同事对象
+     *
+     * @param c 同事对象
+     */
+    public abstract void changed(Colleague c);
+}

src/com/company/mediator/computer/SoundCard.java

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+package com.company.mediator.computer;
+
+/**
+ * 声卡同事
+ */
+public class SoundCard extends Colleague {
+    public SoundCard(Mediator mediator) {
+        super(mediator);
+    }
+
+    /**
+     * 播放音频
+     *
+     * @param data 音频数据
+     */
+    public void soundPlay(String data) {
+        System.out.println("音频： " + data);
+    }
+}

src/com/company/mediator/model/Colleague.java

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+package com.company.mediator.model;
+
+
+//抽象同事
+public abstract class Colleague {
+    protected Mediator mediator;
+
+    public Colleague(Mediator mediator) {
+        this.mediator = mediator;
+    }
+
+    /**
+     * 同事角色的具体行为，由子类实现
+     */
+    public abstract void action();
+}

src/com/company/mediator/model/ConcreteColleagueA.java

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+package com.company.mediator.model;
+
+public class ConcreteColleagueA extends Colleague {
+    public ConcreteColleagueA(Mediator mediator) {
+        super(mediator);
+    }
+
+    @Override
+    public void action() {
+        System.out.println("ColleagueA 将信息递交给中介者处理");
+    }
+}