Java线程池队列LinkedBlockingDeque

public enum QueueTypeEnum {
    ARRAY_BLOCKING_QUEUE(1, "ArrayBlockingQueue"),
    LINKED_BLOCKING_QUEUE(2, "LinkedBlockingQueue"),
    DELAY_QUEUE(3, "DelayQueue"),
    PRIORITY_BLOCKING_QUEUE(4, "PriorityBlockingQueue"),
    SYNCHRONOUS_QUEUE(5, "SynchronousQueue"),
    LINKED_TRANSFER_QUEUE(6, "LinkedTransferQueue"),
    LINKED_BLOCKING_DEQUE(7, "LinkedBlockingDeque"),
    VARIABLE_LINKED_BLOCKING_QUEUE(8, "VariableLinkedBlockingQueue"),
    MEMORY_SAFE_LINKED_BLOCKING_QUEUE(9, "MemorySafeLinkedBlockingQueue");
}

//队列的头节点
transient Node<E> first;
//队列的尾节点
transient Node<E> last;
//队列中元素的个数
private transient int count;
//队列中元素的最大个数
private final int capacity;
//锁
final ReentrantLock lock = new ReentrantLock();
//队列为空时，阻塞take线程的条件队列
private final Condition notEmpty = lock.newCondition();
//队列满时，阻塞put线程的条件队列
private final Condition notFull = lock.newCondition();

public LinkedBlockingDeque() {
    this(Integer.MAX_VALUE);
}
public LinkedBlockingDeque(int capacity) {
    if (capacity <= 0) throw new IllegalArgumentException();
    this.capacity = capacity;
}
public LinkedBlockingDeque(Collection<? extends E> c) {
    this(Integer.MAX_VALUE);
    final ReentrantLock lock = this.lock;
    lock.lock(); // Never contended, but necessary for visibility
    try {
        for (E e : c) {
            if (e == null)
                throw new NullPointerException();
            if (!linkLast(new Node<E>(e)))
                throw new IllegalStateException("Deque full");
        }
    } finally {
        lock.unlock();
    }
}