java设计模式---状态机

待我称王封你为后i 2023-06-26 12:06 13阅读 0赞

### 文章目录 ###

*  应用场景
 *  状态机
 *   *  结果
 *  github
 *  参考博客

# 应用场景 #

对于有不同状态的事件可以采用状态机设计模式。比如电梯的运行，停止等等状态。

# 状态机 #

参考下面博客进行编写，以及进行优化，使用锁进行同步，不足之处多多指教~

模拟各种房间的预定，入住，退房等等…

**定义状态**

public interface State {
    
        /**
         * 预定
         */
        public void bookRoom();
    
        /**
         * 退房
         */
        public void checkOutRoom();
    
        /**
         * 入住
         */
        public void checkInRoom();
    
    }

**各种状态重写**

@Data
    @AllArgsConstructor
    public class CheckInState implements State {
    
        Room room;
    
        @Override
        public void bookRoom() {
            room.setState(room.getBookState());
            System.out.println(Thread.currentThread().getName()+"当前" + room.getRoomId() + "房间预定!");
        }
    
        @Override
        public void checkOutRoom() {
            room.setState(room.getCheckOutState());
            System.out.println(Thread.currentThread().getName()+"当前" + room.getRoomId() + "房间退房!");
        }
    
        @Override
        public void checkInRoom() {
            if (!(room.getState() instanceof CheckInState)) {
                System.out.println(Thread.currentThread().getName()+"当前" + room.getRoomId() + "房间不能入住!");
                return;
            }
            room.setState(room.getCheckInState());
            System.out.println(Thread.currentThread().getName()+"当前" + room.getRoomId() + "房间入住!");
        }
    }

@Data
    @AllArgsConstructor
    public class CheckOutState implements State {
    
        Room room;
    
        @Override
        public void bookRoom() {
            room.setState(room.getBookState());
            System.out.println(Thread.currentThread().getName()+"当前" + room.getRoomId() + "房间被预定!");
        }
    
        @Override
        public void checkOutRoom() {
            if (!(room.getState() instanceof CheckOutState)) {
                System.out.println(Thread.currentThread().getName()+"当前" + room.getRoomId() + "房间不能退订!");
                return;
            }
            room.setState(room.getCheckOutState());
            System.out.println(Thread.currentThread().getName()+"当前" + room.getRoomId() + "房间退订!");
        }
    
        @Override
        public void checkInRoom() {
            room.setState(room.getCheckInState());
            System.out.println(Thread.currentThread().getName()+"当前" + room.getRoomId() + "房间入住!");
        }
    }

@Data
    @AllArgsConstructor
    public class BookState implements State {
    
        Room room;
    
        @Override
        public void bookRoom() {
            if (!(room.getState() instanceof BookState)) {
                System.out.println(Thread.currentThread().getName()+"当前" + room.getRoomId() + "房间不能预定!");
                return;
            }
            room.setState(room.getBookState());
            System.out.println(Thread.currentThread().getName()+"当前" + room.getRoomId() + "房间预定!");
        }
    
        @Override
        public void checkOutRoom() {
            room.setState(room.getCheckOutState());
            System.out.println(Thread.currentThread().getName()+"当前" + room.getRoomId() + "房间退订!");
        }
    
        @Override
        public void checkInRoom() {
            room.setState(room.getCheckInState());
            System.out.println(Thread.currentThread().getName()+"当前" + room.getRoomId() + "房间入住!");
        }
    
    }

**房间类**

@Data
    public class Room {
    
        ReentrantLock reentrantLock = new ReentrantLock();
    
        Integer roomId;
    
        /**
         * 状态
         */
        State state;
    
        CheckInState checkInState;
    
        CheckOutState checkOutState;
    
        BookState bookState;
    
        public Room(Integer roomId) {
            this.roomId = roomId;
            checkInState = new CheckInState(this);
            checkOutState = new CheckOutState(this);
            bookState = new BookState(this);
            state = checkOutState;
        }
    
        /**
         * 预定
         */
        public void bookRoom() {
            state.bookRoom();
        }
    
        /**
         * 退房
         */
        public void checkOutRoom() {
            state.checkOutRoom();
        }
    
        /**
         * 入住
         */
        public void checkInRoom() {
            state.checkInRoom();
        }
    
        @Override
        public String toString() {
            return "该房间" + roomId + "的状态是:" + getState().getClass().getName();
        }
    
    }

**房间初始化**

public class RoomList {
    
        /**
         * 单人间
         */
        public static List<Room> list1 = new ArrayList<>(10);
    
        /**
         * 双人间
         */
        public static List<Room> list2 = new ArrayList<>(10);
    
        static {
            Room room1 = new Room(1);
            Room room2 = new Room(2);
            Room room3 = new Room(3);
            list1.add(room1);
            list1.add(room2);
            list1.add(room3);
            Room room4 = new Room(4);
            Room room5 = new Room(5);
            list2.add(room4);
            list2.add(room5);
        }
    
    }

**测试类**

public class BookTest {
    
        public static void main(String[] args) throws InterruptedException {
            //单人间
            List<Room> list1 = RoomList.list1;
            //双人间
            List<Room> list2 = RoomList.list2;
    
            int b = 0;
            do {
                b++;
                new Thread(() -> {
                    for (Room room : list1) {
                        int i = 0;
                        if (room.getState() instanceof CheckOutState) {
                            room.reentrantLock.lock();
                            i++;
                            System.out.println(Thread.currentThread().getName()+"预定到房间:" + room.getRoomId());
                            room.setState(room.getBookState());
                            room.bookRoom();
                            room.checkInRoom();
                            try {
                                Thread.sleep(4000);
                            } catch (InterruptedException e) {
                                e.printStackTrace();
                            }
                            room.checkOutRoom();
                            room.reentrantLock.unlock();
                            if (i == list1.size()) {
                                System.out.println(Thread.currentThread().getName()+"当前没有房间......");
                            }
                        }
                    }
                }).start();
                new Thread(() -> {
                    int i = 0;
                    for (Room room : list2) {
                        i++;
                        if (room.getState() instanceof CheckOutState) {
                            room.reentrantLock.lock();
                            System.out.println(Thread.currentThread().getName()+"预定到房间:" + room.getRoomId());
                            room.setState(room.getCheckInState());
                            room.checkInRoom();
                            try {
                                Thread.sleep(1000);
                            } catch (InterruptedException e) {
                                e.printStackTrace();
                            }
                            room.checkOutRoom();
                            room.reentrantLock.unlock();
                            if (i == list2.size()) {
                                System.out.println(Thread.currentThread().getName()+"当前没有房间......");
                            }
                        }
                    }
                }).start();
                Thread.sleep(500);
            } while (b < 10);
            Thread.sleep(10000);
            for (Room room : list1) {
                System.out.println(room.getRoomId()+" "+room.getState());
            }
            for (Room room : list2) {
                System.out.println(room.getRoomId()+" "+room.getState());
            }
    
    
        }
    
    }

## 结果 ##

Thread-0预定到房间:1
    Thread-1预定到房间:4
    Thread-0当前1房间预定!
    Thread-0当前1房间入住!
    Thread-1当前4房间入住!
    Thread-2预定到房间:2
    Thread-3预定到房间:5
    Thread-3当前5房间入住!
    Thread-2当前2房间预定!
    Thread-2当前2房间入住!
    Thread-1当前4房间退房!
    Thread-4预定到房间:3
    Thread-4当前3房间预定!
    Thread-4当前3房间入住!
    Thread-5预定到房间:4
    Thread-5当前4房间入住!
    Thread-3当前5房间退房!
    Thread-3当前没有房间......
    Thread-7预定到房间:5
    Thread-7当前5房间入住!
    Thread-5当前4房间退房!
    Thread-9预定到房间:4
    Thread-9当前4房间入住!
    Thread-7当前5房间退房!
    Thread-7当前没有房间......
    Thread-9当前4房间退房!
    Thread-9预定到房间:5
    Thread-9当前5房间入住!
    Thread-13预定到房间:4
    Thread-13当前4房间入住!
    Thread-0当前1房间退房!
    Thread-9当前5房间退房!
    Thread-9当前没有房间......
    Thread-13当前4房间退房!
    Thread-13预定到房间:5
    Thread-13当前5房间入住!
    Thread-16预定到房间:1
    Thread-16当前1房间预定!
    Thread-16当前1房间入住!
    Thread-17预定到房间:4
    Thread-17当前4房间入住!
    Thread-2当前2房间退房!
    Thread-18预定到房间:2
    Thread-18当前2房间预定!
    Thread-18当前2房间入住!
    Thread-4当前3房间退房!
    Thread-13当前5房间退房!
    Thread-13当前没有房间......
    Thread-17当前4房间退房!
    Thread-17预定到房间:5
    Thread-17当前5房间入住!
    Thread-17当前5房间退房!
    Thread-17当前没有房间......
    Thread-16当前1房间退房!
    Thread-16预定到房间:3
    Thread-16当前3房间预定!
    Thread-16当前3房间入住!
    Thread-18当前2房间退房!
    Thread-16当前3房间退房!
    1 CheckOutState(room=该房间1的状态是:com.example.demo.statepackage.CheckOutState)
    2 CheckOutState(room=该房间2的状态是:com.example.demo.statepackage.CheckOutState)
    3 CheckOutState(room=该房间3的状态是:com.example.demo.statepackage.CheckOutState)
    4 CheckOutState(room=该房间4的状态是:com.example.demo.statepackage.CheckOutState)
    5 CheckOutState(room=该房间5的状态是:com.example.demo.statepackage.CheckOutState)

# github #

[Strategy-Pattern][]

# 参考博客 #

[【设计模式读书笔记】状态模式][Link 1]

[Strategy-Pattern]: https://github.com/dajitui/Strategy-Pattern
[Link 1]: http://www.iocoder.cn/DesignPattern/xiaomingge/State-Pattern/