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文章目录
  1. 命令模式

命令模式

  • 将一个请求封装为一个对象，从而使你可用不同的请求对客户进行参数化；对请求排队或记录请求日志，以及支持可撤销的操作。
    Command
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public class Light {
    public void on() {
        System.out.println("灯点亮");
    }
    public void off() {
        System.out.println("灯熄灭");
    }
}
public class TV {
    public void on() {
        System.out.println("TV打开");
    }
    public void off() {
        System.out.println("TV关闭");
    }
}
public interface Command {
    void execute();
}
public class LightOnCommand implements Command{
    private Light light;
    public LightOnCommand(Light light) {
        this.light = light;
    }
    @Override public void execute() {
        light.on();
    }
}
public class LightOffCommand implements Command {
    private Light light;
    public LightOffCommand(Light light) {
        this.light = light;
    }
    @Override public void execute() {
        light.off();
    }
}
public class TVOnCommand implements Command{
    private TV tv;
    public TVOnCommand(TV tv) {
        this.tv = tv;
    }
    @Override public void execute() {
        tv.on();
    }
}
public class TVOffCommand implements Command{
    private TV tv;
    public TVOffCommand(TV tv) {
        this.tv = tv;
    }
    @Override public void execute() {
        tv.off();
    }
}
public class SwitchInvoker {
    private Command onCommand;
    private Command offCommand;
    public void setOnCommand(Command onCommand) {
        this.onCommand = onCommand;
    }
    public void setOffCommand(Command offCommand) {
        this.offCommand = offCommand;
    }
    public void on(){
        onCommand.execute();
    }
    public void off(){
        offCommand.execute();
    }
}
public class App {
    public static void main(String[] args) {
        //购买电器
        Light light=new Light();
        TV tv=new TV();
        //配置电器
        Command lightOnCommand=new LightOnCommand(light);
        Command lightOffCommand=new LightOffCommand(light);
        Command tvOnCommand=new TVOnCommand(tv);
        Command tvOffCommand=new TVOffCommand(tv);
        //安装开关并连接电器
        SwitchInvoker commonSwitch=new SwitchInvoker();
        //这一步相当于用电线将电器与开关相连接
        //开关并不知道要开关谁，
        commonSwitch.setOnCommand(lightOnCommand);
        commonSwitch.setOffCommand(lightOffCommand);
        //操作电器
        commonSwitch.on();
        commonSwitch.off();
        //装修更改线路
        //这里表达"使你可用不同的请求对客户参数化（将客户端参数化）"
        commonSwitch.setOnCommand(tvOnCommand);
        commonSwitch.setOffCommand(tvOffCommand);
        //操作电器
        commonSwitch.on();
        commonSwitch.off();
    }
}
文章目录
  1. 命令模式