【行为型模式】状态模式（state）之23种java设计模式

State接口类

public interface State {
	void handle();
}

BookedState类

/**
 * 已预订状态
 * @author Administrator
 *
 */
public class BookedState implements State {
	@Override
	public void handle() {
		System.out.println("房间已预订！别人不能定！");
	}

}

CheckedInState类

/**
 * 已入住状态
 * @author Administrator
 *
 */
public class CheckedInState implements State {

	@Override
	public void handle() {
		System.out.println("房间已入住！请勿打扰！");
	}

}

FreeState类

/**
 * 空闲状态
 * @author Administrator
 *
 */
public class FreeState implements State {

	@Override
	public void handle() {
		System.out.println("房间空闲！！！没人住！");
	}
}

HomeContext类

/**
 * 房间对象
 * @author Administrator
 *
 */
public class HomeContext {
	//如果是银行系统，这个Context类就是账号。根据金额不同，切换不同的状态！

	private State state;

	public void setState(State s){
		System.out.println("修改状态！");
		state = s;
		state.handle();
	}

}

Client测试类

public class Client {
	public static void main(String[] args) {
		HomeContext ctx = new HomeContext();

		ctx.setState(new FreeState());
		ctx.setState(new BookedState());

	}
}