状态模式

package state;
/***
 * 房间对象
 * 持有不同对象
 * @author zw
 *
 */
public class Context {
	private State state;
	
	public void setState(State state) {
		System.out.println("修改状态");
		this.state = state;
		state.handle();
	}
}

package state;

public interface State {
	void handle();
}

package state;
/***
 * 预定状态 
 * @author zw
 *
 */
public class FreeState implements State{

	@Override
	public void handle() {
		// TODO Auto-generated method stub
		System.out.println("房间已经预定,别人不能预定");
	}

}

package state;
/***
 * 入住 状态 
 * @author zw
 *
 */
public class InState2 implements State{

	@Override
	public void handle() {
		// TODO Auto-generated method stub
		System.out.println("房间已经入住，请勿打扰");
	}

}

package state;
/***
 * 空闲状态
 * @author zw
 *
 */
public class Reserve implements State{

	@Override
	public void handle() {
		// TODO Auto-generated method stub
		System.out.println("房间空闲，没人住");
	}

}

package state;

public class Client {
	public static void main(String[] args) {
		State s1 = new FreeState();
		State s2 = new Reserve();
		State s3 = new InState2();
		
		
		Context c = new Context();
		c.setState(s1);
		c.setState(s2);
		c.setState(s3);
		
	}
}