设计模式之状态模式

状态模式：当一个对象的内在状态改变时允许改变其行为，这个对象看起来像是改变了它的类。

 

public interface State {
    public void handle(Context context);
}

 

public class Context {
    private State state;

    public Context(State state) {
        this.state = state;
    }

    public State getState() {
        return state;
    }

    public void setState(State state) {
        this.state = state;
        System.out.println("当前状态：" + state.getClass().getSimpleName());
    }

    public void request() {
        state.handle(this);
    }
}

 

public class ConcreteStateOne implements State {
    @Override
    public void handle(Context context) {
        context.setState(new ConcreteStateTwo());
    }
}

 

public class ConcreteStateTwo implements State {
    @Override
    public void handle(Context context) {
        context.setState(new ConcreteStateOne());
    }
}

 

public class StateDemo {
    public static void main(String[] args) {
        Context context = new Context(new ConcreteStateOne());
        context.request();
        context.request();
        context.request();
    }
}