ap
Class ListQueue

java.lang.Object
  ap.ListQueue

All Implemented Interfaces:

Queue

public class ListQueue

extends java.lang.Object

implements Queue

A simple yet completely functional implementation of the Queue interface. The interface is part of the AP subset and is testable. This implementation is not part of the subset, but is useful in a classroom setting.

All queue functions execute in O(1) or constant time amortized over several queue operations. This is because the underlying storage is java.util.LinkedList which supports constant time access, add (to end and front), and remove (from end and front).

This implementation is provided at apcentral.

Constructor Summary

ListQueue()
Constructs an initially empty queue.

Method Summary

java.lang.Object	dequeue() Dequeues and returns the first element of the queue.
void	enqueue(java.lang.Object x) Enqueue an element onto the back of this queue.
boolean	isEmpty() Returns true if this queue is empty, otherwise returns false.
java.lang.Object	peekFront() Returns the first element of the queue without dequeuing it.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ListQueue

public ListQueue()

Constructs an initially empty queue.

Method Detail

enqueue

public void enqueue(java.lang.Object x)

Description copied from interface: Queue

Enqueue an element onto the back of this queue.

Specified by:

enqueue in interface Queue

Parameters:

x - is the object enqueued onto this queue.

dequeue

public java.lang.Object dequeue()

Description copied from interface: Queue

Dequeues and returns the first element of the queue.

Specified by:

dequeue in interface Queue

Returns:

the just-dequeued element of the queue

See Also:

Queue.peekFront()

peekFront

public java.lang.Object peekFront()

Description copied from interface: Queue

Returns the first element of the queue without dequeuing it.

Specified by:

peekFront in interface Queue

Returns:

the first element of the queue

See Also:

Queue.dequeue()

isEmpty

public boolean isEmpty()

Description copied from interface: Queue

Returns true if this queue is empty, otherwise returns false.

Specified by:

isEmpty in interface Queue

Returns:

true if this queue is empty, otherwise return false.