java设计模式（六） 命令模式

【命令模式】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。

1，定义命令接口

package com.pattern.command;

public interface Command {

	public void execute();

}

2，接口的实现类

package com.pattern.command;

public class LightOnCommand implements Command{
	Light light;

	public LightOnCommand(Light light){
		this.light = light;
	}

	/**
	 * @see com.pattern.command.Command#execute()
	 */
	@Override
	public void execute() {
		light.on();
	}

}

3，命令的具体执行者

package com.pattern.command;

public class Light {

	public void on(){
		System.out.println("turn on the light!");
	}

}

4，控制器类

package com.pattern.command;

public class SimpleRemoteControl {

	Command slot;

	public SimpleRemoteControl(){}

	public void setCommand(Command command){
		slot = command;
	}

	public void buttonWasPressed(){
		slot.execute();
	}
}

5，测试类

package com.pattern.command;

public class RemoteControlTest {

	public static void main(String[] args) {
		SimpleRemoteControl remote = new SimpleRemoteControl();
		Light light = new Light();
		LightOnCommand lightOn = new LightOnCommand(light);

		remote.setCommand(lightOn);
		remote.buttonWasPressed();
	}
}

输出结果：

turn on the light!