/** * Removes the last element {@code e} such that * {@code o.equals(e)}, if such an element exists in this deque. * If the deque does not contain the element, it is unchanged. * * @param o element to be removed from this deque, if present * @return {@code true} if the deque contained the specified element * @throws NullPointerException if the specified element is null */ public boolean removeLastOccurrence(Object o) { checkNotNull(o); for (Node<E> p = last(); p != null; p = pred(p)) { E item = p.item; if (item != null && o.equals(item) && p.casItem(item, null)) { unlink(p); return true; } } return false; }
/** * Removes the first element {@code e} such that * {@code o.equals(e)}, if such an element exists in this deque. * If the deque does not contain the element, it is unchanged. * * @param o element to be removed from this deque, if present * @return {@code true} if the deque contained the specified element * @throws NullPointerException if the specified element is null */ public boolean removeFirstOccurrence(Object o) { checkNotNull(o); for (Node<E> p = first(); p != null; p = succ(p)) { E item = p.item; if (item != null && o.equals(item) && p.casItem(item, null)) { unlink(p); return true; } } return false; }
/** * Constructs a deque initially containing the elements of * the given collection, added in traversal order of the * collection's iterator. * * @param c the collection of elements to initially contain * @throws NullPointerException if the specified collection or any * of its elements are null */ public ConcurrentLinkedDeque(Collection<? extends E> c) { // Copy c into a private chain of Nodes Node<E> h = null, t = null; for (E e : c) { checkNotNull(e); Node<E> newNode = new Node<E>(e); if (h == null) h = t = newNode; else { t.lazySetNext(newNode); newNode.lazySetPrev(t); t = newNode; } } initHeadTail(h, t); }
checkNotNull(e); final Node<E> newNode = new Node<E>(e);
checkNotNull(e); final Node<E> newNode = new Node<E>(e);
checkNotNull(e); Node<E> newNode = new Node<E>(e); if (beginningOfTheEnd == null)