Java实现状态模式的示例代码_Java

一、简介

1、定义

状态模式 (state pattern)是一种行为型设计模式，允许对象在内部状态改变时改变它的行为。通过定义状态接口和具体状态类，将对象的状态和行为分开，使得状态改变时可以改变行为。

2、状态模式的结构

状态模式涉及以下几个角色：
state（状态接口）：定义了状态类的共同接口，所有具体的状态类都实现这个接口。
concretestate（具体状态类）：每个具体的状态类实现了state接口，并定义了在该状态下的具体行为。
context（上下文）：上下文类维护一个当前状态的引用，它通常会委托给具体的状态类来执行相应的状态切换。

二、java实现案例

1、电灯开关状态案例

/**
 * @description: 状态接口
 * @date: 2025-02-07 17:09
 * @author: gaoyufei
 **/
public interface state {
    void handle(switch context);
}

/**
 * @description: 关灯状态
 * @date: 2025-02-07 17:12
 * @author: gaoyufei
 **/
public class closestate implements state{
    @override
    public void handle(switch switcher) {
        switcher.setstate(new openstate());
        system.out.println("开灯了");
    }
}
/**
 * @description: 开灯状态
 * @date: 2025-02-07 17:11
 * @author: gaoyufei
 **/
public class openstate implements state{
    @override
    public void handle(switch switcher) {
        switcher.setstate(new closestate());
        system.out.println("关灯了");
    }
}
/**
 * @description: 开关，持有灯的状态
 * @date: 2025-02-07 17:08
 * @author: gaoyufei
 **/
public class switch {
    private state state;
    public switch(state state){
        this.state=state;
    }
    public void setstate(state state){
        this.state=state;
    }
    public void press(){
        state.handle(this);
    }
}

/**
 * @description: 操作人
 * @date: 2025-02-07 17:14
 * @author: gaoyufei
 **/
public class operator {
    public static void main(string[] args) throws interruptedexception {
        switch switcher=new switch(new closestate());//初始状态是关灯
        //模拟每隔1秒按压一下开关
        while (true){
            thread.sleep(1000);
            switcher.press();
        }
    }
}

2、番茄工作法状态案例

/**
 * @description: 番茄状态接口
 * @date: 2025-02-08 10:49
 * @author: gaoyufei
 **/
public interface tomatostate {
    void deal(worker worker);
}

/**
 * @description: 番茄-工作状态类
 * @date: 2025-02-08 10:51
 * @author: gaoyufei
 **/
public class worktomatostate implements tomatostate {
    @override
    public void deal(worker worker) {
        system.out.println("休息结束了，开始工作吧");
        try {
            thread.sleep(25*60*1000);
        } catch (interruptedexception e) {
            e.printstacktrace();
        }
        system.out.println("工作了25分钟");
        worker.settomatostate(new resttomatostate());
    }
}

/**
 * @description: 番茄-休息状态类
 * @date: 2025-02-08 10:53
 * @author: gaoyufei
 **/
public class resttomatostate implements tomatostate{
    @override
    public void deal(worker worker) {
        system.out.println("工作结束了，好好休息吧");
        try {
            thread.sleep(5*60*1000);
        } catch (interruptedexception e) {
            e.printstacktrace();
        }
        system.out.println("休息了5分钟");
        worker.settomatostate(new worktomatostate());
    }
}

/**
 * @description: 工作者
 * @date: 2025-02-08 10:51
 * @author: gaoyufei
 **/
public class worker {
    private tomatostate tomatostate;
    public worker(tomatostate tomatostate){
        this.tomatostate=tomatostate;
    }
    public void settomatostate(tomatostate tomatostate){
        this.tomatostate=tomatostate;
    }
    public void starttomatoclock(){
        this.tomatostate.deal(this);
    }
}

/**
 * @description: 客户端
 * @date: 2025-02-08 11:02
 * @author: gaoyufei
 **/
public class client {
    public static void main(string[] args) {
        worker worker=new worker(new worktomatostate());
        while (true){
            worker.starttomatoclock();
        }
    }
}

3、电梯状态案例

这是一个简单的电梯系统。电梯的状态有关门、开门、上升、下降、停止。每个状态下电梯的行为不同。通过状态模式，根据电梯的不同状态执行不同的行为。

/**
 * @description: 电梯状态接口
 * @date: 2025-02-08 9:02
 * @author: gaoyufei
 **/
public interface elevatorstate {
    void opendoor();
    void closedoor();
    void moveup();
    void movedown();
    void stop();
}
/**
 * @description: 关门状态
 * @date: 2025-02-08 9:05
 * @author: gaoyufei
 **/
public class closestate implements elevatorstate {
    private elevator elevator;
    public closestate(elevator elevator){
        this.elevator=elevator;
    }
    @override
    public void opendoor() {
        system.out.println("电梯门开了");
        elevator.setcurrentstate(elevator.getopenstate());
    }
    @override
    public void closedoor() {
        system.out.println("电梯门已经关了");
    }
    @override
    public void moveup() {
        system.out.println("电梯上升");
        elevator.setcurrentstate(elevator.getmovingupstate());
    }
    @override
    public void movedown() {
        system.out.println("电梯下降");
        elevator.setcurrentstate(elevator.getmovingdownstate());
    }
    @override
    public void stop() {
        system.out.println("电梯停止");
        elevator.setcurrentstate(elevator.getstopstate());
    }
}

/**
 * @description: 开门状态
 * @date: 2025-02-08 9:07
 * @author: gaoyufei
 **/
public class openstate implements elevatorstate{
    private elevator elevator;
    public openstate(elevator elevator){
        this.elevator=elevator;
    }
    @override
    public void opendoor() {
        system.out.println("电梯门已经打开");
    }
    @override
    public void closedoor() {
        system.out.println("电梯门关了");
        elevator.setcurrentstate(elevator.getclosestate());
    }
    @override
    public void moveup() {
        system.out.println("电梯门打开状态,不能上升");
    }
    @override
    public void movedown() {
        system.out.println("电梯门打开状态,不能下降");
    }
    @override
    public void stop() {
        system.out.println("电梯门打开状态,不能变换为停止状态");
    }
}

/**
 * @description: 停止状态
 * @date: 2025-02-08 9:59
 * @author: gaoyufei
 **/
public class stopstate implements elevatorstate{
    private elevator elevator;
    public stopstate(elevator elevator){
        this.elevator=elevator;
    }
    @override
    public void opendoor() {
        system.out.println("电梯门开了");
        elevator.setcurrentstate(elevator.getopenstate());
    }
    @override
    public void closedoor() {
        system.out.println("电梯门关了");
        elevator.setcurrentstate(elevator.getclosestate());
    }
    @override
    public void moveup() {
        system.out.println("电梯上升");
        elevator.setcurrentstate(elevator.getmovingupstate());
    }
    @override
    public void movedown() {
        system.out.println("电梯下降");
        elevator.setcurrentstate(elevator.getmovingdownstate());
    }
    @override
    public void stop() {
        system.out.println("电梯停止");
    }
}
/**
 * @description: 上升状态
 * @date: 2025-02-08 9:07
 * @author: gaoyufei
 **/
public class movingupstate implements elevatorstate{
    private elevator elevator;
    public movingupstate(elevator elevator){
        this.elevator=elevator;
    }
    @override
    public void opendoor() {
        system.out.println("电梯正在上升，不能开门");
    }
    @override
    public void closedoor() {
        system.out.println("电梯已经关门");
    }
    @override
    public void moveup() {
        system.out.println("电梯正在上升");
    }
    @override
    public void movedown() {
        system.out.println("电梯下降");
        elevator.setcurrentstate(elevator.getmovingdownstate());
    }
    @override
    public void stop() {
        system.out.println("电梯停止");
        elevator.setcurrentstate(elevator.getstopstate());
    }
}

/**
 * @description: 下降状态
 * @date: 2025-02-08 9:08
 * @author: gaoyufei
 **/
public class movingdownstate implements elevatorstate{
    private elevator elevator;
    public movingdownstate(elevator elevator){
        this.elevator=elevator;
    }
    @override
    public void opendoor() {
        system.out.println("电梯正在下降,不能开门");
    }
    @override
    public void closedoor() {
        system.out.println("电梯正在下降,已经关门了");
    }
    @override
    public void moveup() {
        system.out.println("电梯上升");
        elevator.setcurrentstate(elevator.getmovingupstate());
    }
    @override
    public void movedown() {
        system.out.println("电梯正在下降");
    }
    @override
    public void stop() {
        system.out.println("电梯停止");
        elevator.setcurrentstate(elevator.getstopstate());
    }
}

/**
 * @description: 电梯
 * @date: 2025-02-08 9:04
 * @author: gaoyufei
 **/
public class elevator {
    private elevatorstate closestate;
    private elevatorstate openstate;
    private elevatorstate movingdownstate;
    private elevatorstate movingupstate;
    private elevatorstate stopstate;

    private elevatorstate currentstate;

    public elevator(){
        closestate=new closestate(this);
        openstate=new openstate(this);
        movingdownstate=new movingdownstate(this);
        movingupstate=new movingupstate(this);
        stopstate=new stopstate(this);
        currentstate=closestate;// 默认初始状态为关闭状态

    }
    public void setcurrentstate(elevatorstate currentstate) {
        this.currentstate = currentstate;
    }
    public elevatorstate getclosestate() {
        return closestate;
    }
    public elevatorstate getopenstate() {
        return openstate;
    }
    public elevatorstate getmovingdownstate() {
        return movingdownstate;
    }
    public elevatorstate getmovingupstate() {
        return movingupstate;
    }
    public elevatorstate getstopstate() {
        return stopstate;
    }
    public void opendoor(){
        currentstate.opendoor();
    }
    public void closedoor(){
        currentstate.closedoor();
    }
    public void moveup(){
        currentstate.moveup();
    }
    public void movedown(){
        currentstate.movedown();
    }
    public void stop(){
        currentstate.stop();
    }
}

/**
 * @description: 客户端
 * @date: 2025-02-08 9:29
 * @author: gaoyufei
 **/
public class client {
    public static void main(string[] args) {
        //初始关闭状态
        elevator elevator=new elevator();
        //关门
        elevator.closedoor();//输出 电梯门已经关了
        //开门
        elevator.opendoor();//输出 电梯门开了
        //上升
        elevator.moveup();//输出 电梯门打开状态不能上升
        //关门
        elevator.closedoor();//输出 电梯门关了
        //上升
        elevator.moveup();//输出 电梯上升
        //关门
        elevator.closedoor();//输出 电梯已经关门
        //下降
        elevator.movedown();//输出 电梯下降
        //停止
        elevator.stop();//输出 电梯停止
        //开门
        elevator.opendoor();//输出 电梯门开了
        //停止
        elevator.stop();//输出 电梯门打开状态,不能变换为停止状态
    }
}

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