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@Getter
public static class Context {
    public final static OpeningState OPENING_STATE = new OpeningState();
    public final static ClosingState CLOSING_STATE = new ClosingState();
    public final static RunningState RUNNING_STATE = new RunningState();
    public final static StoppingState STOPPING_STATE = new StoppingState();

    private LiftState liftState;

    public void setLiftState(LiftState liftState) {
        this.liftState = liftState;
        this.liftState.setContext(this);
    }

    public void open() {
        this.liftState.open();
    }
    public void close() {
        this.liftState.close();
    }
    public void run() {
        this.liftState.run();
    }
    public void stop() {
        this.liftState.stop();
    }
}

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@Setter
public static abstract class LiftState {
    protected Context context;
    public abstract void open();
    public abstract void close();
    public abstract void run();
    public abstract void stop();
}

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public static class OpeningState extends LiftState {
    @Override
    public void open() {
        System.out.println("电梯开启。。。");
    }
    @Override
    public void close() {
        super.context.setLiftState(Context.CLOSING_STATE);
        super.context.close();
    }
    @Override
    public void run() {
    }
    @Override
    public void stop() {
    }
}

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public static class ClosingState extends LiftState {
    @Override
    public void close() {
        System.out.println("电梯门关闭...");
    }
    @Override
    public void open() {
        super.context.setLiftState(Context.OPENING_STATE);
        super.context.open();
    }
    @Override
    public void run() {
        super.context.setLiftState(Context.RUNNING_STATE);
        super.context.run();
    }
    @Override
    public void stop() {
        super.context.setLiftState(Context.STOPPING_STATE);
        super.context.stop();
    }
}

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public static class RunningState extends LiftState {
    public void run() {
        System.out.println("电梯正在运行...");
    }
    @Override
    public void open() {
    }
    @Override
    public void close() {
    }
    @Override
    public void stop() {
        super.context.setLiftState(Context.STOPPING_STATE);
        super.context.stop();
    }
}

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public static class StoppingState extends LiftState {
    public void stop() {
        System.out.println("电梯停止了...");
    }
    public void open() {
        super.context.setLiftState(Context.OPENING_STATE);
        super.context.getLiftState().open();
    }
    public void close() {
        super.context.setLiftState(Context.CLOSING_STATE);
        super.context.getLiftState().close();
    }
    public void run() {
        super.context.setLiftState(Context.RUNNING_STATE);
        super.context.getLiftState().run();
    }
}

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Context context = new Context();
context.setLiftState(new ClosingState());

context.open();
context.run();
context.close();
context.stop();

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电梯开启。。。
电梯门关闭...
电梯停止了...