完成命令模式

Author: lijunhuayc

command/lijunhuayc/images/lijunhuayc_resule.png

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+package com.command;
+
+/**
+ * @Desc: 命令对象和接受者对象的组装类[客户角色]
+ * ps：我这把类名定义成ClientRole更方便读者理解这只是命令模式中的一个客户角色，而不是我们常规意义上说的客户端
+ * @author ljh
+ * @date 2015-3-16 上午11:08:03
+ */
+public class ClientRole {
+	
+	/**
+	 * @Description: 组装操作
+	 * @author (ljh) @date 2015-3-16 上午11:13:06  
+	 * @return void
+	 */
+	public void assembleAction() {
+		ReceiverRole receiverRole1 = new ReceiverRole();//创建一个命令接收者
+		Command command1 = new ConcreteCommandImpl1(receiverRole1);//创建一个命令的具体实现对象，并指定命令接收者
+		
+		ReceiverRole receiverRole2 = new ReceiverRole(new PeopleBean(9999, "神仙"));
+		Command command2 = new ConcreteCommandImpl2(receiverRole2);
+		
+		//PS：command1 修改people为(18, "西北狼")
+		//PS：command2 修改people为(35, "lijunhuayc")
+		
+		InvokerRole invokerRole = new InvokerRole();//创建一个命令调用者
+		invokerRole.setCommand1(command1);//为调用者指定命令对象1
+		invokerRole.setCommand2(command2);//为调用者指定命令对象2
+		invokerRole.invoke(null);//发起调用命令请求
+		
+		ReceiverRole receiverRole3 = new ReceiverRole(new PeopleBean(9999, "神仙"));
+		Command command3 = new ConcreteCommandImpl3(receiverRole2);
+		invokerRole.invoke(command3);//发起调用命令请求
+		
+	}
+	
+}

command/lijunhuayc/images/lijunhuayc_uml.jpg

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+package com.command;
+
+/**
+ * @Desc: 命令接口[命令角色]
+ * ps：你也可以定义成abstract class类型	*_*
+ * @author ljh
+ * @date 2015-3-16 上午11:01:01
+ */
+public interface Command {
+	public void execute();
+	public void undo();
+	public void redo();
+	
+}

command/lijunhuayc/readme.md

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+package com.command;
+
+/**
+ * @Desc: 命令接口的实现类[具体命令角色]
+ * @author ljh
+ * @date 2015-3-16 上午11:04:51
+ */
+public class ConcreteCommandImpl1 implements Command{
+	private ReceiverRole receiverRole1;
+
+	public ConcreteCommandImpl1(ReceiverRole receiverRole1) {
+		this.receiverRole1 = receiverRole1;
+	}
+	
+	@Override
+	public void execute() {
+		/*
+		 * 可以加入命令排队等等，未执行的命令支持redo操作
+		 */
+		receiverRole1.opAction(18, "西北狼");//执行具体的命令操作
+	}
+
+	@Override
+	public void undo() {
+		receiverRole1.rollBack();//执行具体的撤销回滚操作
+	}
+
+	@Override
+	public void redo() {
+		//在命令执行前可以修改命令的执行
+	}
+	
+	
+	
+}

command/lijunhuayc/resource/command/ClientRole.java

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+package com.command;
+
+/**
+ * @Desc: 命令接口的实现类[具体命令角色]
+ * @author ljh
+ * @date 2015-3-16 上午11:04:51
+ */
+public class ConcreteCommandImpl2 implements Command{
+	private ReceiverRole receiverRole1;
+
+	public ConcreteCommandImpl2(ReceiverRole receiverRole1) {
+		this.receiverRole1 = receiverRole1;
+	}
+	
+	@Override
+	public void execute() {
+		/*
+		 * 可以加入命令排队等等，未执行的命令支持redo操作
+		 */
+		receiverRole1.opAction(35, "lijunhuayc");//执行具体的命令操作
+	}
+
+	@Override
+	public void undo() {
+		receiverRole1.rollBack();//执行具体的撤销回滚操作
+	}
+
+	@Override
+	public void redo() {
+		//在命令执行前可以修改命令的执行
+	}
+	
+	
+	
+}

command/lijunhuayc/resource/command/Command.java

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+package com.command;
+
+/**
+ * @Desc: 命令接口的实现类[具体命令角色]
+ * @author ljh
+ * @date 2015-3-16 上午11:04:51
+ */
+public class ConcreteCommandImpl3 implements Command{
+	private ReceiverRole receiverRole1;
+
+	public ConcreteCommandImpl3(ReceiverRole receiverRole1) {
+		this.receiverRole1 = receiverRole1;
+	}
+	
+	@Override
+	public void execute() {
+		/*
+		 * 可以加入命令排队等等，未执行的命令支持redo操作
+		 */
+		receiverRole1.opAction(9999, "神仙");//执行具体的命令操作
+	}
+
+	@Override
+	public void undo() {
+		receiverRole1.rollBack();//执行具体的撤销回滚操作
+	}
+
+	@Override
+	public void redo() {
+		//在命令执行前可以修改命令的执行
+	}
+	
+	
+	
+}

command/lijunhuayc/resource/command/ConcreteCommandImpl1.java

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+package com.command;
+
+/**
+ * @Desc: 命令调用[调用者角色]
+ * ps:使用命令对象的入口，扶着调用命令对象执行请求
+ * @author ljh
+ * @date 2015-3-16 上午11:16:15
+ */
+public class InvokerRole {
+	private Command command1;
+	private Command command2;
+	//持有多个命令对象[实际的情况也可能是一个命令对象的集合来保存命令对象]
+	
+	public void setCommand1(Command command1) {
+		this.command1 = command1;
+	}
+	public void setCommand2(Command command2) {
+		this.command2 = command2;
+	}
+	
+	public void invoke(Command command) {
+		//根据具体情况选择执行某些命令
+		if(null != command){
+			command.execute();
+			return;
+		}
+		command1.execute();
+		command2.execute();
+	}
+	
+	
+	
+}

command/lijunhuayc/resource/command/ConcreteCommandImpl2.java

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+package com.command;
+
+
+public class MainTest {
+	
+	public static void main(String[] args) {
+		ClientRole client = new ClientRole();
+		client.assembleAction();
+		
+	}
+	
+}

command/lijunhuayc/resource/command/ConcreteCommandImpl3.java

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+package com.command;
+
+/**
+ * @Desc: 辅助类，作为接收者Receiver的成员，包含两个属性，用来观察命令的执行情况
+ * @author ljh
+ * @date 2015-3-16 上午11:29:11
+ */
+public class PeopleBean {
+	private int age = -1;	//年龄
+	private String name = "NULL";	//姓名
+	
+	public PeopleBean() {
+	}
+	public PeopleBean(int age, String name) {
+		this.age = age;
+		this.name = name;
+	}
+	
+	public void update(int age, String name) {
+		this.age = age;
+		this.name = name;
+	}
+	
+	/**
+	 * @return 返回一个PeopleBean的克隆对象
+	 */
+	protected PeopleBean clone(){
+		return new PeopleBean(age, name);
+	}
+	
+	/**
+	 * @Description: 还原操作
+	 * @author (ljh) @date 2015-3-16 上午11:45:23 
+	 * @param cache 
+	 * @return void
+	 */
+	protected void undo(PeopleBean cache) {
+		this.age = cache.age;
+		this.name = cache.name;
+	}
+	
+	@Override
+	public String toString() {
+		return " 【姓名：" + name + "\t年龄：" + age + "】\n";
+	}
+	
+}

command/lijunhuayc/resource/command/InvokerRole.java

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+package com.command;
+
+/**
+ * @Desc: 命令的具体执行类[接受者角色]
+ * ps：命令接收者可以是任意的类，只要实现了命令要求实现的相应功能即可。
+ * @author ljh
+ * @date 2015-3-16 上午11:06:14
+ */
+public class ReceiverRole {
+	private PeopleBean people;
+	private PeopleBean peopleCache = new PeopleBean(); //具体命令操作的缓存栈，用于回滚。这里为了方便就用一个PeopleBean来代替[实际的使用情况可能是需要回滚多个命令，这里只回滚一次]
+	
+	public ReceiverRole() {
+		this.people = new PeopleBean(-1, "NULL");//初始化年龄为-1，姓名为NULL
+	}
+	
+	public ReceiverRole(PeopleBean people) {
+		this.people = people;
+	}
+	
+	/**
+	 * @Description: 具体操作方法[修改年龄和姓名]
+	 * @author (ljh) @date 2015-3-16 上午11:07:32  
+	 * @return void
+	 */
+	public void opAction(int age, String name) {
+		peopleCache = people.clone();//缓存people
+		people.update(age, name);
+		System.out.println("执行命令后："+people.toString());
+	}
+	
+	/**
+	 * @Description: 回滚操作，用于撤销opAction执行的改变
+	 * @author (ljh) @date 2015-3-16 上午11:34:41  
+	 * @return void
+	 */
+	public void rollBack() {
+		people.undo(peopleCache);
+		System.out.println("命令回滚后："+people.toString());
+	}
+	
+}