小狗的状态

小狗在不同环境条件下可能呈现不同的状态表现，要求用接口封装小狗的状态。

代码如下：

interface DogState{
	public void showState();
}


class SoftlyState implements DogState {
	public void showState(){
		System.out.println("听主人的命令！");
	}
}

class MeetEnemyState implements DogState {
	public void showState(){
		System.out.println("上去咬一口！");
	}
}

class MeetFriendState implements DogState {
	public void showState(){
		System.out.println("晃动尾巴，以示友好！");
	}
}

class MeetAnotherDog implements DogState {
	public void showState(){
		System.out.println("hello！");
	}
}

class Dog{
	DogState state;
	public void show(){
		state.showState();
	}
	public void setState(DogState s){
		state=s;
	}
}

public class CheckDogState{
	public static void main(String[] args) {
		Dog yellowDog=new Dog();
		System.out.println("狗在主人面前：");
		yellowDog.setState(new SoftlyState());
		yellowDog.show();
		System.out.println("狗遇到敌人：");
		yellowDog.setState(new MeetEnemyState());
		yellowDog.show();
		System.out.println("狗遇到朋友：");
		yellowDog.setState(new MeetFriendState());
		yellowDog.show();
		System.out.println("狗遇到同伴：");
		yellowDog.setState(new MeetAnotherDog());
		yellowDog.show();
		
	}
}