qingcheng-houduan/src/test/java/com/greenorange/promotion/light/CommandPatternExample.java

package com.greenorange.promotion.light;

public class CommandPatternExample {

    // 命令接口
    public interface Command {
        void execute();
    }

    // 接收者类：开灯
    public static class Light {
        public void on() {
            System.out.println("灯已开启");
        }

        public void off() {
            System.out.println("灯已关闭");
        }
    }

    // 接收者类：开电视
    public static class TV {
        public void on() {
            System.out.println("电视已开启");
        }

        public void off() {
            System.out.println("电视已关闭");
        }
    }

    // 具体命令类：开灯命令
    public static class LightOnCommand implements Command {
        private Light light;

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

        @Override
        public void execute() {
            light.on();  // 执行开灯操作
        }
    }

    // 具体命令类：开电视命令
    public static class TVOnCommand implements Command {
        private TV tv;

        public TVOnCommand(TV tv) {
            this.tv = tv;
        }

        @Override
        public void execute() {
            tv.on();  // 执行开电视操作
        }
    }

    // 调用者类：遥控器
    public static class RemoteControl {
        private Command command;

        public void setCommand(Command command) {
            this.command = command;
        }

        public void pressButton() {
            command.execute();  // 执行命令
        }
    }

    // 测试类：命令模式的客户端
    public static void main(String[] args) {
        // 创建接收者
        Light light = new Light();
        TV tv = new TV();

        // 创建命令
        Command lightOn = new LightOnCommand(light);
        Command tvOn = new TVOnCommand(tv);

        // 创建遥控器
        RemoteControl remote = new RemoteControl();

        // 开灯
        remote.setCommand(lightOn);
        remote.pressButton();  // 输出: 灯已开启

        // 开电视
        remote.setCommand(tvOn);
        remote.pressButton();  // 输出: 电视已开启
    }
}