设计模式笔记之五 命令模式

 
命令模式的定义： 将请求封装成对象，以便使用不同的请求、队列或者日志来参数化其他对象。命令模式也支持可撤销的操作。
 
uml图（暂略）
 
例子：
 

/** * 命令接口类 */public interface icommand {		/**	 * 执行接口	 */	public void execute();		/**	 * 撤销接口	 */	public void undo();}/** * 具体的命令实现类1 */public class concretecommand1 implements icommand {	private receiver1 receiver;		public concretecommand1(receiver1 receiver) {			this.receiver = receiver;	}		@override	public void execute() {				system.out.println("concretecommand1 execute...");		receiver.dosomething();	}	@override	public void undo() {				system.out.println("concretecommand1 undo...");		receiver.dosomething2();	}	}/** * 具体的命令实现类2 */public class concretecommand2 implements icommand {	private receiver2 receiver;		public concretecommand2(receiver2 receiver) {			this.receiver = receiver;	}		@override	public void execute() {				system.out.println("concretecommand2 execute...");		receiver.dosomething();	}	@override	public void undo() {				system.out.println("concretecommand2 undo...");		receiver.dosomething2();	}	}/** * 命令接收者1 */public class receiver1 {	/**	 * 命令具体实现	 */	public void dosomething() {				system.out.println("receiver1 dosomething...");	}		/**	 * 命令具体实现	 */	public void dosomething2() {				system.out.println("receiver1 dosomething2...");	}	}/** * 命令接收者2 */public class receiver2 {	/**	 * 命令具体实现	 */	public void dosomething() {				system.out.println("receiver2 dosomething...");	}		/**	 * 命令具体实现	 */	public void dosomething2() {				system.out.println("receiver2 dosomething2...");	}	}/** * 命令模式的使用 */public class testcommand {	/**	 * @param args	 */	public static void main(string[] args) {				icommand command1 = new concretecommand1(new receiver1());		command1.execute();		command1.undo();				icommand command2 = new concretecommand2(new receiver2());		command2.execute();		command2.undo();			}}