Class Queue<E>

java.lang.Object

Queue<E>

All Implemented Interfaces:

QueueADT<E>

public class Queue<E>
extends java.lang.Object
implements QueueADT<E>

An ordered collection of items, where items are added to the rear and removed from the front.

Constructor Summary

Constructors

Constructor and Description
Queue()

Method Summary

Modifier and Type	Method and Description
void	clear() Removes all items in the queue leaving an empty queue.
E	dequeue() Removes an item from the front of the Queue and returns it.
void	enqueue(E item) Adds an item to the rear of the queue.
private void	expandCapacity()
boolean	isEmpty() Returns true iff the Queue is empty.
E	peek() Returns the item at front of the Queue without removing it.
int	size() Returns the number of items in the Queue.

Methods inherited from class java.lang.Object

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

Constructor Detail

Queue

public Queue()

Method Detail

enqueue

public void enqueue(E item)

Adds an item to the rear of the queue.

Specified by:

enqueue in interface QueueADT<E>

Parameters:

item - the item to add to the queue.

Throws:

java.lang.IllegalArgumentException - if item is null.

dequeue

public E dequeue()

Removes an item from the front of the Queue and returns it.

Specified by:

dequeue in interface QueueADT<E>

Returns:

the front item in the queue.

Throws:

EmptyQueueException - if the queue is empty.

peek

public E peek()

Returns the item at front of the Queue without removing it.

Specified by:

peek in interface QueueADT<E>

Returns:

the front item in the queue.

Throws:

EmptyQueueException - if the queue is empty.

isEmpty

public boolean isEmpty()

Returns true iff the Queue is empty.

Specified by:

isEmpty in interface QueueADT<E>

Returns:

true if queue is empty; otherwise false.

clear

public void clear()

Removes all items in the queue leaving an empty queue.

Specified by:

clear in interface QueueADT<E>

size

public int size()

Returns the number of items in the Queue.

Specified by:

size in interface QueueADT<E>

Returns:

the size of the queue.

expandCapacity

private void expandCapacity()