Java中常用阻塞队列的问题小结

final Object[] items;


int takeIndex;


int putIndex;

public ArrayBlockingQueue(int capacity, boolean fair) {
    if (capacity <= 0)
        throw new IllegalArgumentException();
    
    this.items = new Object[capacity]; 
    lock = new ReentrantLock(fair);
    notEmpty = lock.newCondition();
    notFull =  lock.newCondition();
}

public boolean offer(E e) {
    checkNotNull(e);
    final ReentrantLock lock = this.lock;
    lock.lock();
    try {
        if (count == items.length)
            return false;
        else {
            enqueue(e);
            return true;
        }
    } finally {
        lock.unlock();
    }
}

public void put(E e) throws InterruptedException {
    checkNotNull(e);
    final ReentrantLock lock = this.lock;
    lock.lockInterruptibly();
    try {
        while (count == items.length)
            notFull.await();
        enqueue(e);
    } finally {
        lock.unlock();
    }
}

private E dequeue() {
    // assert lock.getHoldCount() == 1;
    // assert items[takeIndex] != null;
    final Object[] items = this.items;
    @SuppressWarnings("unchecked")
    E x = (E) items[takeIndex];
    items[takeIndex] = null;
    if (++takeIndex == items.length)
        takeIndex = 0;
    count--;
    if (itrs != null)
        itrs.elementDequeued();
    notFull.signal(); // 出队后唤醒生产者线程
    return x;
}

public LinkedBlockingQueue() {
    this(Integer.MAX_VALUE);
}


public LinkedBlockingQueue(int capacity) {
    if (capacity <= 0) throw new IllegalArgumentException();
    this.capacity = capacity;
    last = head = new node<E>(null);
}

public class ProducerConsumer {

    private static BlockingQueue<String> queue = new ArrayBlockingQueue<>(5);
    private static class Producer extends Thread {
        @Override
        public void run() {
            try {
                queue.put("product");
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.print("produce..");
        }
    }
    private static class Consumer extends Thread {
                String product = queue.take();
            System.out.print("consume..");
}
public static void main(String[] args) {
    for (int i = 0; i < 2; i++) {
        Producer producer = new Producer();
        producer.start();
    for (int i = 0; i < 5; i++) {
        Consumer consumer = new Consumer();
        consumer.start();
    for (int i = 0; i < 3; i++) {
output：
produce..produce..consume..consume..produce..consume..produce..consume..produce..consume..