阻塞queue系列之LinkedBlockingQueue

LinkedBlockingQueue繼承AbstractQueue，實現了BlockingQueue，Serializable接口。內部使用單向鏈表存儲數據。可定義容量，默認初始化容量是Integer最大值（可能出現內存溢出）。插入和取出使用不同的鎖，putLock插入鎖，takeLock取出鎖，添加和刪除數據的時候可以並行。多CPU情況下可以同一時刻既消費又生產。LinkedBlockingQueue在大多數併發的場景下吞吐量比ArrayBlockingQueue，但是性能不穩定。

    private final ReentrantLock takeLock = new ReentrantLock();

    /** Wait queue for waiting takes */
    private final Condition notEmpty = takeLock.newCondition();

    /** Lock held by put, offer, etc */
    private final ReentrantLock putLock = new ReentrantLock();

    /** Wait queue for waiting puts */
    private final Condition notFull = putLock.newCondition();

構造函數

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 LinkedBlockingQueue(Collection<? extends E> c) {
        this(Integer.MAX_VALUE);
        final ReentrantLock putLock = this.putLock;
        putLock.lock(); // Never contended, but necessary for visibility
        try {
            int n = 0;
            for (E e : c) {
                if (e == null)
                    throw new NullPointerException();
                if (n == capacity)
                    throw new IllegalStateException("Queue full");
                enqueue(new Node<E>(e));
                ++n;
            }
            count.set(n);
        } finally {
            putLock.unlock();
        }
    }

常用方法

常用方法與ArrayBlockingQueue類似，方法具體實現可以參考源碼。ArrayBlockingQueue