Method Detail

• size

  int size()

  Returns the number of elements in the queue.

  Returns:

  number of elements in the queue

• isEmpty

  boolean isEmpty()

  Tests whether the queue is empty.

  Returns:

  true if the queue is empty, false otherwise

• enqueue

  void enqueue(E e)

  Inserts an element at the rear of the queue.

  Parameters:

  e - the element to be inserted

• first

  E first()

  Returns, but does not remove, the first element of the queue.

  Returns:

  the first element of the queue (or null if empty)

• dequeue

  E dequeue()

  Removes and returns the first element of the queue.

  Returns:

  element removed (or null if empty)