标签：
命令模式：
将请求封装成对象，从而使用不同的请求、队列以及日志来参数化其他对象。命令对象支持可撤销的操作。命令对象将动作和接收者包进对象中。实现“行为请求者”与“行为实现者”解耦。
要点： 命令对象中动作和接收者被绑在一起，控制器调用命令对象的execute方法。
应用： 线程池、队列请求、日志请求。
类图：
以下程序模拟一个控制器对客厅的灯和车库的门进行控制。
1.定义灯
package net.dp.command.simpleremote;
public class Light {
public Light() {
}
public void on() {
System.out.println("Light is on");
}
public void off() {
System.out.println("Light is off");
}
}
2.定义车库的门
package net.dp.command.simpleremote;
public class GarageDoor {
public GarageDoor() {
}
public void up() {
System.out.println("Garage Door is Open");
}
public void down() {
System.out.println("Garage Door is Closed");
}
public void stop() {
System.out.println("Garage Door is Stopped");
}
public void lightOn() {
System.out.println("Garage light is on");
}
public void lightOff() {
System.out.println("Garage light is off");
}
}
3.定义命令接口
package net.dp.command.simpleremote;
public interface Command {
public void execute();
}
4.实现命令接口
package net.dp.command.simpleremote;
public class LightOnCommand implements Command {
Light light;
public LightOnCommand(Light light) {
this.light = light;
}
public void execute() {
light.on();
}
}
package net.dp.command.simpleremote;
public class LightOffCommand implements Command {
Light light;
public LightOffCommand(Light light) {
this.light = light;
}
public void execute() {
light.off();
}
}
package net.dp.command.simpleremote;
public class GarageDoorOpenCommand implements Command {
GarageDoor garageDoor;
public GarageDoorOpenCommand(GarageDoor garageDoor) {
this.garageDoor = garageDoor;
}
public void execute() {
garageDoor.up();
}
}
5.编写控制器，实现命令的调用
package net.dp.command.simpleremote;
//
// This is the invoker
//
public class SimpleRemoteControl {
Command slot;
public SimpleRemoteControl() {}
public void setCommand(Command command) {
slot = command;
}
public void buttonWasPressed() {
slot.execute();
}
}
6.写完啦！！
package net.dp.command.simpleremote;
public class RemoteControlTest {
public static void main(String[] args) {
SimpleRemoteControl remote = new SimpleRemoteControl();
Light light = new Light();
GarageDoor garageDoor = new GarageDoor();
LightOnCommand lightOn = new LightOnCommand(light);
GarageDoorOpenCommand garageOpen = new GarageDoorOpenCommand(garageDoor);
remote.setCommand(lightOn);
remote.buttonWasPressed();
remote.setCommand(garageOpen);
remote.buttonWasPressed();
}
}
标签：
原文地址：http://www.cnblogs.com/lcqBlogs/p/4278236.html
