命令模式-接收者與執行者解耦和

Gatlin發表於2019-01-19

老闆:阿飛,我們們公司又接了個新專案,一個客戶,,臥室和客廳很大,電燈電視開關也不好找,所以希望製造一個遙控器來控制一些傢俱的開啟與關閉,目前需要5個按鍵,臥室的燈,臥室的電視,客廳的燈,客廳的電視,在留一個預備按鍵。我等會把需求文件給你。
專案組長阿飛:好的,老闆
專案組長阿飛:小三,來了個需求,你看下,你先設計一下架構
阿三:好的,飛哥

三天過後:飛哥,好了,你看下

先設計了一個介面,裡面包含了,每一個按鈕的統一行為

package com.commandPattern.command;

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

    //執行方法
    public void exceute();

}

然後建立了一個物件,代表了空物件,什麼操作也不執行

package com.commandPattern.command.nullCommand;

import com.commandPattern.command.Command;

/**
 * @program: testPattern
 * @description: 建立一個空物件,在許多設計模式種,都會看到空物件的使用,甚至有些時候,空物件本身也被視為一種設計模式
 * @author: Mr.Yang
 * @create: 2018-12-08 17:40
 **/
public class NullCommand implements Command {
    public void exceute() {
        System.out.println("什麼都不做處理");
    }
}

燈的具體類

package com.commandPattern.entity;

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

    /**
     * name為燈的具體裝飾,即為哪裡的燈
     * @param name
     */
    public  Lamp(String name){
        this.name=name;
    }
    public void  on (){
        System.out.println(name+"_燈開啟");
    }
    public void off (){
        System.out.println(name+"_燈關閉");
    }
}

電視的具體類

package com.commandPattern.entity;

/**
 * @program: testPattern
 * @description: 電視的具體類
 * @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+"_電視開啟");
    }
    public void off(){
        System.out.println(name+"_電視關閉");
    }
}

關閉燈的具體命令

package com.commandPattern.command.off;

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

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

    Lamp lamp;

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

開啟燈的具體命令

package com.commandPattern.command.on;

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

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

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

    //燈開啟的命令
    public void exceute() {
        lamp.on();
    }
}

電視關閉的具體命令

package com.commandPattern.command.off;

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

/**
 * @program: testPattern
 * @description: 電視關閉
 * @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();
    }
}

電視開啟的具體命令

package com.commandPattern.command.on;

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

/**
 * @program: testPattern
 * @description: 電視開啟
 * @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();
    }
}

建立一個遙控器

package com.commandPattern.control;

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

import java.util.Arrays;

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

    Command[] onCommand;
    Command[] offCommand;

    //初始化每個操作為空操作
    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();
    }

    /**
     * 輸出每個按鈕的具體代表類
     * @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("
");
        }
        return sb.toString();
    }
}

測試類

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();

        /**
         * 建立裝置到合適位置
         */
        Tv bedRoomTV = new Tv("臥室");
        Tv drawiTV = new Tv("客廳");

        Lamp bedRoomLamp = new Lamp("臥室");
        Lamp drawiLamp = new Lamp("客廳");

        /**
         * 建立所有命令操作物件
         */
        //臥室燈關閉物件
        LampOffCommand bedLampOffCommand = new LampOffCommand(bedRoomLamp);
        //臥室燈開啟物件
        LampOnCommand bedLampOnCommand = new LampOnCommand(bedRoomLamp);
        //臥室TV關閉物件
        TvOffCommand bedTvOffCommand = new TvOffCommand(bedRoomTV);
        //臥室TV開啟物件
        TvOnCommand bedTVcommand = new TvOnCommand(bedRoomTV);
        //客廳燈開啟物件
        LampOnCommand drawLampOnCommand = new LampOnCommand(drawiLamp);
        //客廳燈關閉物件
        LampOffCommand drawLampOffCommand = new LampOffCommand(drawiLamp);
        //客廳TV關閉物件
        TvOffCommand drawTVOffCommand = new TvOffCommand(drawiTV);
        //客廳TV開啟物件
        TvOnCommand drawTVOnCommand = new TvOnCommand(drawiTV);

        System.out.println("---------------------------------------------未賦值之前------------------------------------------------");
        System.out.println(remoteControl);
        System.out.println("******************************************************************************************************");

        /**
         * //將操作物件與卡槽一一對應
         */
        //賦值臥室燈開啟與關閉
        remoteControl.setCommond(0,bedLampOnCommand,bedLampOffCommand);
        //賦值臥室TV開啟與關閉
        remoteControl.setCommond(1,bedTVcommand,bedTvOffCommand);
        //賦值客廳燈開啟與關閉
        remoteControl.setCommond(2,drawLampOnCommand,drawLampOffCommand);
        //賦值客廳TV開啟與關閉
        remoteControl.setCommond(3,drawTVOnCommand,drawTVOffCommand);

        System.out.println("---------------------------------------------賦值之後------------------------------------------------");
        System.out.println(remoteControl);
        System.out.println("******************************************************************************************************");


        /**
         * 測試每一個按鈕
         */
        remoteControl.clickOn(0);
        remoteControl.clickOff(0);

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

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

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


    }
}

測試結果

---------------------------------------------未賦值之前------------------------------------------------
[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

******************************************************************************************************
---------------------------------------------賦值之後------------------------------------------------
[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

******************************************************************************************************
臥室_燈開啟
臥室_燈關閉
臥室_電視開啟
臥室_電視關閉
客廳_燈開啟
客廳_燈關閉
客廳_電視開啟
客廳_電視關閉

阿三:飛哥,我這裡使用的設計模式-命令模式,
將動作執行(LampOnCommand,TvOnCommand……)與接收者(Lamp,Tv)包裝到物件裡面,對外暴露的只有一個Command介面中的execute方法,其他物件不需要知道那個接收者執行了什麼動作,只需要知道呼叫execute,就能完成一個請求的操作,這個物件,與其他物件沒有關聯,完全解耦和,如果需要做新增,不需要修改原有程式碼,擴充接收者類和動作執行類,就能實現功能。

專案組長阿飛:不錯,不錯,進步很大。
專案組長阿飛:第5個按鈕可能需要做一個恢復上一步動作的效果,類似於CTRL+Z這個效果,你再改改把。
阿三:好的。
阿三:飛哥修改好了,你看下

命令介面新增撤銷方法

package com.commandPattern.command;

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

    //執行方法
    public void exceute();

    //撤銷方法
    public void revoke();

}

建立一個空物件,實現了撤銷方法

package com.commandPattern.command.nullCommand;

import com.commandPattern.command.Command;

/**
 * @program: testPattern
 * @description: 建立一個空物件,在許多設計模式種,都會看到空物件的使用,甚至有些時候,空物件本身也被視為一種設計模式
 * @author: Mr.Yang
 * @create: 2018-12-08 17:40
 **/
public class NullCommand implements Command {
    public void exceute() {
        System.out.println("什麼都不做處理");
    }

    public void revoke() {
        System.out.println("什麼都不做處理");
    }
}

燈關閉實現了撤銷方法

package com.commandPattern.command.off;

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

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

    Lamp lamp;

    public LampOffCommand(Lamp lamp){
        this.lamp=lamp;
    }
    //燈關閉
    public void exceute() {
        lamp.off();
    }
    //執行到這個具體實現類,代表上一步是燈關閉,撤銷操作即為燈開啟
    public void revoke() {
        lamp.on();
    }
}

燈開啟實現了撤銷方法

package com.commandPattern.command.on;

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

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

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

    //燈開啟的命令
    public void exceute() {
        lamp.on();
    }
    //執行到這個具體實現類,代表上一步是燈開啟,撤銷操作即為燈關閉
    public void revoke() {
        lamp.off();
    }
}

電視關閉實現了撤銷方法

package com.commandPattern.command.off;

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

/**
 * @program: testPattern
 * @description: 電視關閉
 * @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();
    }
    //執行到這個具體實現類,代表上一步是電視關閉,撤銷操作即為電視開啟
    public void revoke() {
        tv.on();
    }
}

電視開啟實現了撤銷方法

package com.commandPattern.command.on;

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

/**
 * @program: testPattern
 * @description: 電視開啟
 * @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();
    }
    //執行到這個具體實現類,代表上一步是電視開啟,撤銷操作即為電視關閉
    public void revoke() {
        tv.off();
    }
}

遙控器類,新增變數記錄上一步操作

package com.commandPattern.control;

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

import java.util.Arrays;

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

    Command[] onCommand;
    Command[] offCommand;
    //這個變數來記錄上一個命令
    Command upStepCommand;
    //初始化每個操作為空操作
    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記錄上一步命令
    public void clickOn(int index){
        onCommand[index].exceute();
        upStepCommand=onCommand[index];
    }
    //新增upStepCommand記錄上一步命令
    public void clickOff(int index){
        offCommand[index].exceute();
        upStepCommand=offCommand[index];
    }

    public void toUpStepClick(){
        System.out.println("---撤銷---");
        upStepCommand.revoke();
    }
    /**
     * 輸出每個按鈕的具體代表類
     * @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("
");
        }
        return sb.toString();
    }
}

測試類新增撤銷測試

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();

        /**
         * 建立裝置到合適位置
         */
        Tv bedRoomTV = new Tv("臥室");
        Tv drawiTV = new Tv("客廳");

        Lamp bedRoomLamp = new Lamp("臥室");
        Lamp drawiLamp = new Lamp("客廳");

        /**
         * 建立所有命令操作物件
         */
        //臥室燈關閉物件
        LampOffCommand bedLampOffCommand = new LampOffCommand(bedRoomLamp);
        //臥室燈開啟物件
        LampOnCommand bedLampOnCommand = new LampOnCommand(bedRoomLamp);
        //臥室TV關閉物件
        TvOffCommand bedTvOffCommand = new TvOffCommand(bedRoomTV);
        //臥室TV開啟物件
        TvOnCommand bedTVcommand = new TvOnCommand(bedRoomTV);
        //客廳燈開啟物件
        LampOnCommand drawLampOnCommand = new LampOnCommand(drawiLamp);
        //客廳燈關閉物件
        LampOffCommand drawLampOffCommand = new LampOffCommand(drawiLamp);
        //客廳TV關閉物件
        TvOffCommand drawTVOffCommand = new TvOffCommand(drawiTV);
        //客廳TV開啟物件
        TvOnCommand drawTVOnCommand = new TvOnCommand(drawiTV);

        System.out.println("---------------------------------------------未賦值之前------------------------------------------------");
        System.out.println(remoteControl);
        System.out.println("******************************************************************************************************");

        /**
         * //將操作物件與卡槽一一對應
         */
        //賦值臥室燈開啟與關閉
        remoteControl.setCommond(0,bedLampOnCommand,bedLampOffCommand);
        //賦值臥室TV開啟與關閉
        remoteControl.setCommond(1,bedTVcommand,bedTvOffCommand);
        //賦值客廳燈開啟與關閉
        remoteControl.setCommond(2,drawLampOnCommand,drawLampOffCommand);
        //賦值客廳TV開啟與關閉
        remoteControl.setCommond(3,drawTVOnCommand,drawTVOffCommand);

        System.out.println("---------------------------------------------賦值之後------------------------------------------------");
        System.out.println(remoteControl);
        System.out.println("******************************************************************************************************");


        /**
         * 測試每一個按鈕
         */
        remoteControl.clickOn(0);
        remoteControl.clickOff(0);

        //撤銷一次
        remoteControl.toUpStepClick();
        System.out.println("
");

        //撤銷一次
        remoteControl.toUpStepClick();
        System.out.println("
");

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

        //撤銷一次
        remoteControl.toUpStepClick();
        System.out.println("
");

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

        //撤銷一次
        remoteControl.toUpStepClick();
        System.out.println("
");

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

        //撤銷一次
        remoteControl.toUpStepClick();
        System.out.println("
");

    }
}

修改之後的測試結果

---------------------------------------------未賦值之前------------------------------------------------
[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

******************************************************************************************************
---------------------------------------------賦值之後------------------------------------------------
[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

******************************************************************************************************
臥室_燈開啟
臥室_燈關閉
---撤銷---
臥室_燈開啟


---撤銷---
臥室_燈開啟


臥室_電視開啟
臥室_電視關閉
---撤銷---
臥室_電視開啟


客廳_燈開啟
客廳_燈關閉
---撤銷---
客廳_燈開啟


客廳_電視開啟
客廳_電視關閉
---撤銷---
客廳_電視開啟

專案組長阿飛:不錯,不錯,以後給你漲工資。

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