Method Detail

• size

  int size()

  Returns the number of elements in the deque.

  Returns:

  number of elements in the deque

• isEmpty

  boolean isEmpty()

  Tests whether the deque is empty.

  Returns:

  true if the deque is empty, false otherwise

• first

  E first()

  Returns (but does not remove) the first element of the deque.

  Returns:

  first element of the deque (or null if empty)

• last

  E last()

  Returns (but does not remove) the last element of the deque.

  Returns:

  last element of the deque (or null if empty)

• addFirst

  void addFirst(E e)

  Inserts an element at the front of the deque.

  Parameters:

  e - the new element

• addLast

  void addLast(E e)

  Inserts an element at the back of the deque.

  Parameters:

  e - the new element

• removeFirst

  E removeFirst()

  Removes and returns the first element of the deque.

  Returns:

  element removed (or null if empty)

• removeLast

  E removeLast()

  Removes and returns the last element of the deque.

  Returns:

  element removed (or null if empty)