命令模式-接收者与执行者解耦和

2018-12-09 11:20:15来源：博客园阅读 ()

老板：阿飞，咱们公司又接了个新项目，一个客户，，卧室和客厅很大，电灯电视开关也不好找，所以希望制造一个遥控器来控制一些家具的开启与关闭，目前需要5个按键，卧室的灯，卧室的电视，客厅的灯，客厅的电视，在留一个预备按键。我等会把需求文档给你。
项目组长阿飞：好的，老板
项目组长阿飞：小三，来了个需求，你看下，你先设计一下架构
阿三：好的，飞哥

三天过后：飞哥，好了，你看下

先设计了一个接口，里面包含了，每一个按钮的统一行为

 1 package com.commandPattern.command;
 2 
 3 /**
 4 * @program: testPattern
 5 * @description: 命令接口
 6 * @author: Mr.Yang
 7 * @create: 2018-12-08 13:54
 8 **/
 9 public interface Command {
10 
11 //执行方法
12 public void exceute();
13 
14 }

View Code

然后建立了一个对象，代表了空对象，什么操作也不执行

package com.commandPattern.command.nullCommand;

import com.commandPattern.command.Command;

/**
* @program: testPattern
* @description: 建立一个空对象，在许多设计模式种，都会看到空对象的使用，甚至有些时候，空对象本身也被视为一种设计模式
* @author: Mr.Yang
* @create: 2018-12-08 17:40
**/
public class NullCommand implements Command {
public void exceute() {
System.out.println("什么都不做处理");
}
}

灯的具体类

package com.commandPattern.entity;

/**
* @program: testPattern
* @description: 灯的具体类
* @author: Mr.Yang
* @create: 2018-12-08 17:31
**/
public class Lamp {
private String name;

/**
* name为灯的具体装饰，即为哪里的灯
* @param name
*/
public Lamp(String name){
this.name=name;
}
public void on (){
System.out.println(name+"_灯打开");
}
public void off (){
System.out.println(name+"_灯关闭");
}
}

电视的具体类

package com.commandPattern.entity;

/**
* @program: testPattern
* @description: 电视的具体类
* @author: Mr.Yang
* @create: 2018-12-08 17:35
**/
public class Tv {
private String name;
public Tv(String name){
this.name=name;
}
public void on (){
System.out.println(name+"_电视打开");
}
public void off(){
System.out.println(name+"_电视关闭");
}
}

关闭灯的具体命令

package com.commandPattern.command.off;

import com.commandPattern.command.Command;
import com.commandPattern.entity.Lamp;

/**
* @program: testPattern
* @description: 灯关闭
* @author: Mr.Yang
* @create: 2018-12-08 17:33
**/
public class LampOffCommand implements Command {

Lamp lamp;

public LampOffCommand(Lamp lamp){
this.lamp=lamp;
}
//灯关闭
public void exceute() {
lamp.off();
}
}

打开灯的具体命令

package com.commandPattern.command.on;

import com.commandPattern.command.Command;
import com.commandPattern.entity.Lamp;

/**
* @program: testPattern
* @description: 灯打开的命令
* @author: Mr.Yang
* @create: 2018-12-08 17:29
**/
public class LampOnCommand implements Command {

Lamp lamp;
public LampOnCommand(Lamp lamp){
this.lamp=lamp;
}

//灯打开的命令
public void exceute() {
lamp.on();
}
}

电视关闭的具体命令

package com.commandPattern.command.off;

import com.commandPattern.command.Command;
import com.commandPattern.entity.Tv;

/**
* @program: testPattern
* @description: 电视关闭
* @author: Mr.Yang
* @create: 2018-12-08 17:36
**/
public class TvOffCommand implements Command {
Tv tv;
public TvOffCommand(Tv tv){
this.tv=tv;
}
public void exceute() {
tv.off();
}
}

电视打开的具体命令

package com.commandPattern.command.on;

import com.commandPattern.command.Command;
import com.commandPattern.entity.Tv;

/**
* @program: testPattern
* @description: 电视打开
* @author: Mr.Yang
* @create: 2018-12-08 17:37
**/
public class TvOnCommand implements Command {
Tv tv;
public TvOnCommand(Tv tv){
this.tv=tv;
}

public void exceute() {
tv.on();
}
}

建立一个遥控器

package com.commandPattern.control;

import com.commandPattern.command.Command;
import com.commandPattern.command.nullCommand.NullCommand;

import java.util.Arrays;

/**
* @program: testPattern
* @description: 遥控器
* @author: Mr.Yang
* @create: 2018-12-08 17:39
**/
public class RemoteControl {

Command[] onCommand;
Command[] offCommand;

//初始化每个操作为空操作
public RemoteControl(){
onCommand=new Command[5];
offCommand=new Command[5];
NullCommand nullCommand = new NullCommand();
for (int i = 0; i < 5; i++) {
onCommand[i]=nullCommand;
offCommand[i]=nullCommand;
}
}

public void setCommond(int index,Command onCommand,Command offCommand){
this.offCommand[index]=offCommand;
this.onCommand[index]=onCommand;
}

public void clickOn(int index){
onCommand[index].exceute();
}

public void clickOff(int index){
offCommand[index].exceute();
}

/**
* 输出每个按钮的具体代表类
* @return
*/
@Override
public String toString() {
StringBuffer sb = new StringBuffer();
for (int i = 0; i < onCommand.length; i++) {
sb.append("[index : "+i+"] ");
sb.append(onCommand[i].getClass().getName());
sb.append(" ");
sb.append(offCommand[i].getClass().getName());
sb.append("\r\n");
}
return sb.toString();
}
}

测试类

 1 package com.commandPattern.testPattern;
 2 
 3 import com.commandPattern.command.off.LampOffCommand;
 4 import com.commandPattern.command.off.TvOffCommand;
 5 import com.commandPattern.command.on.LampOnCommand;
 6 import com.commandPattern.command.on.TvOnCommand;
 7 import com.commandPattern.control.RemoteControl;
 8 import com.commandPattern.entity.Lamp;
 9 import com.commandPattern.entity.Tv;
10 
11 /**
12 * @program: test
13 * @description:
14 * @author: Mr.Yang
15 * @create: 2018-12-08 17:48
16 **/
17 public class TestPattern {
18 public static void main(String[] args) {
19 RemoteControl remoteControl = new RemoteControl();
20 
21 /**
22 * 创建装置到合适位置
23 */
24 Tv bedRoomTV = new Tv("卧室");
25 Tv drawiTV = new Tv("客厅");
26 
27 Lamp bedRoomLamp = new Lamp("卧室");
28 Lamp drawiLamp = new Lamp("客厅");
29 
30 /**
31 * 创建所有命令操作对象
32 */
33 //卧室灯关闭对象
34 LampOffCommand bedLampOffCommand = new LampOffCommand(bedRoomLamp);
35 //卧室灯打开对象
36 LampOnCommand bedLampOnCommand = new LampOnCommand(bedRoomLamp);
37 //卧室TV关闭对象
38 TvOffCommand bedTvOffCommand = new TvOffCommand(bedRoomTV);
39 //卧室TV打开对象
40 TvOnCommand bedTVcommand = new TvOnCommand(bedRoomTV);
41 //客厅灯打开对象
42 LampOnCommand drawLampOnCommand = new LampOnCommand(drawiLamp);
43 //客厅灯关闭对象
44 LampOffCommand drawLampOffCommand = new LampOffCommand(drawiLamp);
45 //客厅TV关闭对象
46 TvOffCommand drawTVOffCommand = new TvOffCommand(drawiTV);
47 //客厅TV打开对象
48 TvOnCommand drawTVOnCommand = new TvOnCommand(drawiTV);
49 
50 System.out.println("---------------------------------------------未赋值之前------------------------------------------------");
51 System.out.println(remoteControl);
52 System.out.println("******************************************************************************************************");
53 
54 /**
55 * //将操作对象与卡槽一一对应
56 */
57 //赋值卧室灯打开与关闭
58 remoteControl.setCommond(0,bedLampOnCommand,bedLampOffCommand);
59 //赋值卧室TV打开与关闭
60 remoteControl.setCommond(1,bedTVcommand,bedTvOffCommand);
61 //赋值客厅灯打开与关闭
62 remoteControl.setCommond(2,drawLampOnCommand,drawLampOffCommand);
63 //赋值客厅TV打开与关闭
64 remoteControl.setCommond(3,drawTVOnCommand,drawTVOffCommand);
65 
66 System.out.println("---------------------------------------------赋值之后------------------------------------------------");
67 System.out.println(remoteControl);
68 System.out.println("******************************************************************************************************");
69 
70 
71 /**
72 * 测试每一个按钮
73 */
74 remoteControl.clickOn(0);
75 remoteControl.clickOff(0);
76 
77 remoteControl.clickOn(1);
78 remoteControl.clickOff(1);
79 
80 remoteControl.clickOn(2);
81 remoteControl.clickOff(2);
82 
83 remoteControl.clickOn(3);
84 remoteControl.clickOff(3);
85 
86 
87 }
88 }

View Code

测试结果

---------------------------------------------未赋值之前------------------------------------------------
[index : 0] com.commandPattern.command.nullCommand.NullCommand com.commandPattern.command.nullCommand.NullCommand
[index : 1] com.commandPattern.command.nullCommand.NullCommand com.commandPattern.command.nullCommand.NullCommand
[index : 2] com.commandPattern.command.nullCommand.NullCommand com.commandPattern.command.nullCommand.NullCommand
[index : 3] com.commandPattern.command.nullCommand.NullCommand com.commandPattern.command.nullCommand.NullCommand
[index : 4] com.commandPattern.command.nullCommand.NullCommand com.commandPattern.command.nullCommand.NullCommand

******************************************************************************************************
---------------------------------------------赋值之后------------------------------------------------
[index : 0] com.commandPattern.command.on.LampOnCommand com.commandPattern.command.off.LampOffCommand
[index : 1] com.commandPattern.command.on.TvOnCommand com.commandPattern.command.off.TvOffCommand
[index : 2] com.commandPattern.command.on.LampOnCommand com.commandPattern.command.off.LampOffCommand
[index : 3] com.commandPattern.command.on.TvOnCommand com.commandPattern.command.off.TvOffCommand
[index : 4] com.commandPattern.command.nullCommand.NullCommand com.commandPattern.command.nullCommand.NullCommand

******************************************************************************************************
卧室_灯打开
卧室_灯关闭
卧室_电视打开
卧室_电视关闭
客厅_灯打开
客厅_灯关闭
客厅_电视打开
客厅_电视关闭

View Code

阿三：飞哥，我这里使用的设计模式-命令模式，
将动作执行（LampOnCommand，TvOnCommand……）与接收者（Lamp，Tv）包装到对象里面，对外暴露的只有一个Command接口中的execute方法，其他对象不需要知道那个接收者执行了什么动作，只需要知道调用execute，就能完成一个请求的操作，这个对象，与其他对象没有关联，完全解耦和，如果需要做新增，不需要修改原有代码，拓展接收者类和动作执行类，就能实现功能。

项目组长阿飞：不错，不错，进步很大。
项目组长阿飞：第5个按钮可能需要做一个恢复上一步动作的效果，类似于CTRL+Z这个效果，你再改改把。
阿三：好的。
阿三：飞哥修改好了，你看下

命令接口新增撤销方法

package com.commandPattern.command;

/**
* @program: testPattern
* @description: 命令接口
* @author: Mr.Yang
* @create: 2018-12-08 13:54
**/
public interface Command {

//执行方法
public void exceute();

//撤销方法
public void revoke();

}

建立一个空对象,实现了撤销方法

package com.commandPattern.command.nullCommand;

import com.commandPattern.command.Command;

/**
* @program: testPattern
* @description: 建立一个空对象，在许多设计模式种，都会看到空对象的使用，甚至有些时候，空对象本身也被视为一种设计模式
* @author: Mr.Yang
* @create: 2018-12-08 17:40
**/
public class NullCommand implements Command {
public void exceute() {
System.out.println("什么都不做处理");
}

public void revoke() {
System.out.println("什么都不做处理");
}
}

灯关闭实现了撤销方法

package com.commandPattern.command.off;

import com.commandPattern.command.Command;
import com.commandPattern.entity.Lamp;

/**
* @program: testPattern
* @description: 灯关闭
* @author: Mr.Yang
* @create: 2018-12-08 17:33
**/
public class LampOffCommand implements Command {

Lamp lamp;

public LampOffCommand(Lamp lamp){
this.lamp=lamp;
}
//灯关闭
public void exceute() {
lamp.off();
}
//执行到这个具体实现类，代表上一步是灯关闭，撤销操作即为灯打开
public void revoke() {
lamp.on();
}
}

灯打开实现了撤销方法

package com.commandPattern.command.on;

import com.commandPattern.command.Command;
import com.commandPattern.entity.Lamp;

/**
* @program: testPattern
* @description: 灯打开的命令
* @author: Mr.Yang
* @create: 2018-12-08 17:29
**/
public class LampOnCommand implements Command {

Lamp lamp;
public LampOnCommand(Lamp lamp){
this.lamp=lamp;
}

//灯打开的命令
public void exceute() {
lamp.on();
}
//执行到这个具体实现类，代表上一步是灯打开，撤销操作即为灯关闭
public void revoke() {
lamp.off();
}
}

电视关闭实现了撤销方法

package com.commandPattern.command.off;

import com.commandPattern.command.Command;
import com.commandPattern.entity.Tv;

/**
* @program: testPattern
* @description: 电视关闭
* @author: Mr.Yang
* @create: 2018-12-08 17:36
**/
public class TvOffCommand implements Command {
Tv tv;
public TvOffCommand(Tv tv){
this.tv=tv;
}
public void exceute() {
tv.off();
}
//执行到这个具体实现类，代表上一步是电视关闭，撤销操作即为电视打开
public void revoke() {
tv.on();
}
}

电视打开实现了撤销方法

package com.commandPattern.command.on;

import com.commandPattern.command.Command;
import com.commandPattern.entity.Tv;

/**
* @program: testPattern
* @description: 电视打开
* @author: Mr.Yang
* @create: 2018-12-08 17:37
**/
public class TvOnCommand implements Command {
Tv tv;
public TvOnCommand(Tv tv){
this.tv=tv;
}

public void exceute() {
tv.on();
}
//执行到这个具体实现类，代表上一步是电视打开，撤销操作即为电视关闭
public void revoke() {
tv.off();
}
}

遥控器类，新增变量记录上一步操作

package com.commandPattern.control;

import com.commandPattern.command.Command;
import com.commandPattern.command.nullCommand.NullCommand;

import java.util.Arrays;

/**
 * @program: testPattern
 * @description: 遥控器
 * @author: Mr.Yang
 * @create: 2018-12-08 17:39
 **/
public class RemoteControl {

    Command[] onCommand;
    Command[] offCommand;
    //这个变量来记录上一个命令
    Command upStepCommand;
    //初始化每个操作为空操作
    public RemoteControl(){
        onCommand=new Command[5];
        offCommand=new Command[5];
        NullCommand nullCommand = new NullCommand();
        for (int i = 0; i < 5; i++) {
            onCommand[i]=nullCommand;
            offCommand[i]=nullCommand;
        }
        upStepCommand=nullCommand;
    }

    public void setCommond(int index,Command onCommand,Command offCommand){
        this.offCommand[index]=offCommand;
        this.onCommand[index]=onCommand;
    }
    //新增upStepCommand记录上一步命令
    public void clickOn(int index){
        onCommand[index].exceute();
        upStepCommand=onCommand[index];
    }
    //新增upStepCommand记录上一步命令
    public void clickOff(int index){
        offCommand[index].exceute();
        upStepCommand=offCommand[index];
    }

    public void toUpStepClick(){
        System.out.println("---撤销---");
        upStepCommand.revoke();
    }
    /**
     * 输出每个按钮的具体代表类
     * @return
     */
    @Override
    public String toString() {
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < onCommand.length; i++) {
            sb.append("[index : "+i+"]   ");
            sb.append(onCommand[i].getClass().getName());
            sb.append("    ");
            sb.append(offCommand[i].getClass().getName());
            sb.append("\r\n");
        }
        return sb.toString();
    }
}

View Code

测试类新增撤销测试

package com.commandPattern.testPattern;

import com.commandPattern.command.off.LampOffCommand;
import com.commandPattern.command.off.TvOffCommand;
import com.commandPattern.command.on.LampOnCommand;
import com.commandPattern.command.on.TvOnCommand;
import com.commandPattern.control.RemoteControl;
import com.commandPattern.entity.Lamp;
import com.commandPattern.entity.Tv;

/**
 * @program: test
 * @description:
 * @author: Mr.Yang
 * @create: 2018-12-08 17:48
 **/
public class TestPattern {
    public static void main(String[] args) {
        RemoteControl remoteControl = new RemoteControl();

        /**
         * 创建装置到合适位置
         */
        Tv bedRoomTV = new Tv("卧室");
        Tv drawiTV = new Tv("客厅");

        Lamp bedRoomLamp = new Lamp("卧室");
        Lamp drawiLamp = new Lamp("客厅");

        /**
         * 创建所有命令操作对象
         */
        //卧室灯关闭对象
        LampOffCommand bedLampOffCommand = new LampOffCommand(bedRoomLamp);
        //卧室灯打开对象
        LampOnCommand bedLampOnCommand = new LampOnCommand(bedRoomLamp);
        //卧室TV关闭对象
        TvOffCommand bedTvOffCommand = new TvOffCommand(bedRoomTV);
        //卧室TV打开对象
        TvOnCommand bedTVcommand = new TvOnCommand(bedRoomTV);
        //客厅灯打开对象
        LampOnCommand drawLampOnCommand = new LampOnCommand(drawiLamp);
        //客厅灯关闭对象
        LampOffCommand drawLampOffCommand = new LampOffCommand(drawiLamp);
        //客厅TV关闭对象
        TvOffCommand drawTVOffCommand = new TvOffCommand(drawiTV);
        //客厅TV打开对象
        TvOnCommand drawTVOnCommand = new TvOnCommand(drawiTV);

        System.out.println("---------------------------------------------未赋值之前------------------------------------------------");
        System.out.println(remoteControl);
        System.out.println("******************************************************************************************************");

        /**
         * //将操作对象与卡槽一一对应
         */
        //赋值卧室灯打开与关闭
        remoteControl.setCommond(0,bedLampOnCommand,bedLampOffCommand);
        //赋值卧室TV打开与关闭
        remoteControl.setCommond(1,bedTVcommand,bedTvOffCommand);
        //赋值客厅灯打开与关闭
        remoteControl.setCommond(2,drawLampOnCommand,drawLampOffCommand);
        //赋值客厅TV打开与关闭
        remoteControl.setCommond(3,drawTVOnCommand,drawTVOffCommand);

        System.out.println("---------------------------------------------赋值之后------------------------------------------------");
        System.out.println(remoteControl);
        System.out.println("******************************************************************************************************");


        /**
         * 测试每一个按钮
         */
        remoteControl.clickOn(0);
        remoteControl.clickOff(0);

        //撤销一次
        remoteControl.toUpStepClick();
        System.out.println("\r\n");

        //撤销一次
        remoteControl.toUpStepClick();
        System.out.println("\r\n");

        remoteControl.clickOn(1);
        remoteControl.clickOff(1);

        //撤销一次
        remoteControl.toUpStepClick();
        System.out.println("\r\n");

        remoteControl.clickOn(2);
        remoteControl.clickOff(2);

        //撤销一次
        remoteControl.toUpStepClick();
        System.out.println("\r\n");

        remoteControl.clickOn(3);
        remoteControl.clickOff(3);

        //撤销一次
        remoteControl.toUpStepClick();
        System.out.println("\r\n");

    }
}

View Code

修改之后的测试结果

---------------------------------------------未赋值之前------------------------------------------------
[index : 0] com.commandPattern.command.nullCommand.NullCommand com.commandPattern.command.nullCommand.NullCommand
[index : 1] com.commandPattern.command.nullCommand.NullCommand com.commandPattern.command.nullCommand.NullCommand
[index : 2] com.commandPattern.command.nullCommand.NullCommand com.commandPattern.command.nullCommand.NullCommand
[index : 3] com.commandPattern.command.nullCommand.NullCommand com.commandPattern.command.nullCommand.NullCommand
[index : 4] com.commandPattern.command.nullCommand.NullCommand com.commandPattern.command.nullCommand.NullCommand

******************************************************************************************************
---------------------------------------------赋值之后------------------------------------------------
[index : 0] com.commandPattern.command.on.LampOnCommand com.commandPattern.command.off.LampOffCommand
[index : 1] com.commandPattern.command.on.TvOnCommand com.commandPattern.command.off.TvOffCommand
[index : 2] com.commandPattern.command.on.LampOnCommand com.commandPattern.command.off.LampOffCommand
[index : 3] com.commandPattern.command.on.TvOnCommand com.commandPattern.command.off.TvOffCommand
[index : 4] com.commandPattern.command.nullCommand.NullCommand com.commandPattern.command.nullCommand.NullCommand

******************************************************************************************************
卧室_灯打开
卧室_灯关闭
---撤销---
卧室_灯打开


---撤销---
卧室_灯打开


卧室_电视打开
卧室_电视关闭
---撤销---
卧室_电视打开


客厅_灯打开
客厅_灯关闭
---撤销---
客厅_灯打开


客厅_电视打开
客厅_电视关闭
---撤销---
客厅_电视打开