How to use

AbstractNodeQueue

in

akka.dispatch

/**
 * Query the queue whether it is empty right now.
 * 
 * This method can be used from any thread.
 * 
 * @return true if queue was empty at some point in the past
 */
public final boolean isEmpty() {
  return Unsafe.instance.getObjectVolatile(this, tailOffset) == get();
}

/**
 * Add an element to the head of the queue, providing the queue node to be used.
 * 
 * This method can be used from any thread.
 * 
 * @param n the node containing the element to be added; both must not be null
 */
public final void addNode(final Node<T> n) {
  n.setNext(null);
  getAndSet(n).setNext(n);
}

/**
 * Query the queue tail for the next element without dequeuing it.
 * 
 * Use this method only from the consumer thread!
 * 
 * @return element if there was one, or null if there was none
 */
public final T peek() {
  final Node<T> n = peekNode();
  return (n != null) ? n.value : null;
}

protected AbstractNodeQueue() {
  final Node<T> n = new Node<T>();
  _tailDoNotCallMeDirectly = n;
  set(n);
}

/**
 * Pull one item from the queue’s tail if there is one.
 * 
 * Use this method only from the consumer thread!
 * 
 * @return element if there was one, or null if there was none
 */
public final T poll() {
  final Node<T> next = pollNode();
  if (next == null) return null;
  else {
   T value = next.value;
   next.value = null;
   return value;
  }
}

/**
 * Query the queue whether it is empty right now.
 * 
 * This method can be used from any thread.
 * 
 * @return true if queue was empty at some point in the past
 */
public final boolean isEmpty() {
  return peek() == null;
}

protected AbstractNodeQueue() {
  final Node<T> n = new Node<T>();
  _tailDoNotCallMeDirectly = n;
  set(n);
}

/**
 * Pull one item from the queue’s tail if there is one.
 * 
 * Use this method only from the consumer thread!
 * 
 * @return element if there was one, or null if there was none
 */
public final T poll() {
  final Node<T> next = pollNode();
  if (next == null) return null;
  else {
   T value = next.value;
   next.value = null;
   return value;
  }
}

/**
 * Query the queue whether it is empty right now.
 * 
 * This method can be used from any thread.
 * 
 * @return true if queue was empty at some point in the past
 */
public final boolean isEmpty() {
  return peek() == null;
}

/**
 * Query the queue whether it is empty right now.
 * 
 * This method can be used from any thread.
 * 
 * @return true if queue was empty at some point in the past
 */
public final boolean isEmpty() {
  return Unsafe.instance.getObjectVolatile(this, tailOffset) == get();
}

/**
 * Add an element to the head of the queue.
 * 
 * This method can be used from any thread.
 * 
 * @param value the element to be added; must not be null
 */
public final void add(final T value) {
  final Node<T> n = new Node<T>(value);
  getAndSet(n).setNext(n);
}

/**
 * Query the queue tail for the next element without dequeuing it.
 * 
 * Use this method only from the consumer thread!
 * 
 * @return element if there was one, or null if there was none
 */
public final T peek() {
  final Node<T> n = peekNode();
  return (n != null) ? n.value : null;
}

protected AbstractNodeQueue() {
  final Node<T> n = new Node<T>();
  _tailDoNotCallMeDirectly = n;
  set(n);
}

/**
 * Pull one item from the queue’s tail if there is one.
 * 
 * Use this method only from the consumer thread!
 * 
 * @return element if there was one, or null if there was none
 */
public final T poll() {
  final Node<T> next = pollNode();
  if (next == null) return null;
  else {
   T value = next.value;
   next.value = null;
   return value;
  }
}

/**
 * Query the queue whether it is empty right now.
 * 
 * This method can be used from any thread.
 * 
 * @return true if queue was empty at some point in the past
 */
public final boolean isEmpty() {
  return peek() == null;
}

/**
 * Query the queue whether it is empty right now.
 * 
 * This method can be used from any thread.
 * 
 * @return true if queue was empty at some point in the past
 */
public final boolean isEmpty() {
  return Unsafe.instance.getObjectVolatile(this, tailOffset) == get();
}

/**
 * Add an element to the head of the queue, providing the queue node to be used.
 * 
 * This method can be used from any thread.
 * 
 * @param n the node containing the element to be added; both must not be null
 */
public final void addNode(final Node<T> n) {
  n.setNext(null);
  getAndSet(n).setNext(n);
}

/**
 * Query the queue tail for the next element without dequeuing it.
 * 
 * Use this method only from the consumer thread!
 * 
 * @return element if there was one, or null if there was none
 */
public final T peek() {
  final Node<T> n = peekNode();
  return (n != null) ? n.value : null;
}

protected AbstractNodeQueue() {
  final Node<T> n = new Node<T>();
  _tailDoNotCallMeDirectly = n;
  set(n);
}

/**
 * Pull one item from the queue’s tail if there is one.
 * 
 * Use this method only from the consumer thread!
 * 
 * @return element if there was one, or null if there was none
 */
public final T poll() {
  final Node<T> next = pollNode();
  if (next == null) return null;
  else {
   T value = next.value;
   next.value = null;
   return value;
  }
}