设计模式 状态模式

解决  对象发生变化时 其所能做的操作也会发生变化

酒店房间定房系统 房间状态 

如果空闲的时候可以 预定房间 也可以入住 这样的判断 会让代码有很多的逻辑

 

state模式代码实现订房系统

 

   public abstract class abState
    {
        public abstract string getState();
        public abstract void book(Room room);
        public abstract void checkin(Room room);
        public abstract void unbook(Room room);
        public abstract void checkout(Room room);


    }

 

 public class Room
    {

        private abState state;

        public string GetState() 
        {
           return this.state.getState();
        }
        public void setState(abState _state) 
        {
            state = _state;
        }
        public void book() 
        {
            this.state.book(this);
        }
        public void unbook()
        {
            this.state.unbook(this);
        }
        public void checkin()
        {
            this.state.checkin(this);
        }
        public void checkout()
        {
            this.state.checkout(this);
        }
    }

 

  class BookState : abState
    {
        public override string getState()
        {
            return "当前为预订状态";
        }

        public override void book(Room room)
        {
            Console.WriteLine("当前为预订状态，无法再次预订操作");
          
        }

        public override void checkin(Room room)
        {
            Console.WriteLine("当前为预订状态，行进入住操作");
            room.setState(new CheckinState());
        }

        public override void unbook(Room room)
        {
            Console.WriteLine("当前为预订状态，进行取消操作");
            room.setState(new FreeState());
        }

        public override void checkout(Room room)
        {
            Console.WriteLine("当前为预订状态，无法进行退房操作");
        }
    }

 

 class CheckinState : abState
    {
        public override string getState()
        {
            return "当前为入住状态";
        }

        public override void book(Room room)
        {
            Console.WriteLine("当前为入住状态，无法进行预订操作");
           // room.setState(new BookState());
        }

        public override void checkin(Room room)
        {
            Console.WriteLine("当前为入住状态，无法入住操作");
        }

        public override void unbook(Room room)
        {
            Console.WriteLine("当前为入住状态，无法取消预订操作");
        }

        public override void checkout(Room room)
        {
            Console.WriteLine("当前为入住状态，进行退房操作");
            room.setState(new FreeState());
        }
    }

 

 class FreeState:abState
    {
        public override string getState()
        {
            return "当前为空闲状态";
        }

        public override void book(Room room)
        {
            Console.WriteLine("当前为空闲状态，进行预订操作");
            room.setState(new BookState());
        }

        public override void checkin(Room room)
        {
            Console.WriteLine("当前为空闲状态，行进入住操作");
            room.setState(new CheckinState());
        }

        public override void unbook(Room room)
        {
            Console.WriteLine("当前为空闲状态，无法取消预约");
        }

        public override void checkout(Room room)
        {
            Console.WriteLine("当前为空闲状态，无法进行退房操作");
        }
    }

 

 Room room = new Room();
            abState s = new FreeState();
            room.setState(s);
            Console.WriteLine("======================");
            Console.WriteLine(room.GetState());
            Console.WriteLine("======================");
            room.checkin();
            Console.WriteLine(room.GetState());
            Console.WriteLine("======================");
            room.book();
            Console.WriteLine(room.GetState());
            Console.WriteLine("======================");
            room.checkout();
            Console.WriteLine(room.GetState());
            Console.WriteLine("======================");
            Console.ReadKey();