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import java.util.LinkedList;
import java.util.Queue;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;

public class BlockingQueue<T> {
    private final Queue<T> queue = new LinkedList();
    private final int capacity;
    private final ReentrantLock lock = new ReentrantLock();
    //条件变量，用于通知队列非空。
    //Condition 是 Java java.util.concurrent.locks 包中的一个接口，通常与 ReentrantLock 一起使用，提供了一种线程间通信的机制，允许线程在某些条件不满足时等待，直到被其他线程唤醒。
    private final Condition notEmpty = lock.newCondition();
    //条件变量，用于通知队列不满。
    private final Condition notFull = lock.newCondition();

    //构造函数
    public BlockingQueue(int capacity) {
        if (capacity <= 0) throw new IllegalArgumentException("Capacity must be greater than 0");
        this.capacity = capacity;
    }

    //put方法
    public void put(T element) throws InterruptedException {
        lock.lock();
        try {
            // 容量已满，通知等待队列等待
            while (queue.size() == capacity) {
                notFull.await();
            }
            queue.add(element);
            // 通知等待队列非空的线程
            notEmpty.signal();
        } finally {
            lock.unlock();
        }
    }

    //get方法
    public T take() throws InterruptedException {
        lock.lock();
        try {
            // 等待队列非空
            while (queue.isEmpty()) {
                notEmpty.await();
            }
            T element = queue.poll();
            // 通知等待队列不满的线程
            notFull.signal();
            return element;
        } finally {
            lock.unlock();
        }
    }

    public int size() {
        lock.lock();
        try {
            return queue.size();
        } finally {
            lock.unlock();
        }
    }

    public boolean isEmpty() {
        lock.lock();
        try {
            return queue.isEmpty();
        } finally {
            lock.unlock();
        }
    }

    public boolean isFull() {
        lock.lock();
        try {
            return queue.size() == capacity;
        } finally {
            lock.unlock();
        }
    }
}

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public class BlockingQueueTest {
    public static void main(String[] args) {
        BlockingQueue<Integer> queue = new BlockingQueue<>(5);

        // 生产者线程
        Thread producer = new Thread(() -> {
            for (int i = 0; i < 10; i++) {
                try {
                    System.out.println("Produced: " + i);
                    queue.put(i);
                    Thread.sleep((int) (Math.random() * 1000));
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        });

        // 消费者线程
        Thread consumer = new Thread(() -> {
            for (int i = 0; i < 10; i++) {
                try {
                    Integer value = queue.take();
                    System.out.println("Consumed: " + value);
                    Thread.sleep((int) (Math.random() * 1000));
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        });

        producer.start();
        consumer.start();
    }
}