net.datastructures
Class NodeQueue

java.lang.Object
  net.datastructures.NodeQueue

All Implemented Interfaces:

Queue

public class NodeQueue

extends Object

implements Queue

Realization of a queue by means of a singly-linked list of nodes. All operations are performed in constant time.

Author:

Roberto Tamassia

Field Summary

protected Node	head
protected int	size
protected Node	tail

Constructor Summary

NodeQueue()
Creates an empty queue.

Method Summary

Object	dequeue() Removes the element at the front of the queue.
void	enqueue(Object obj) Inserts an element at the rear of the queue.
Object	front() Inspects the element at the front of the queue.
boolean	isEmpty() Returns whether the queue is empty.
int	size() Returns the number of elements in the queue.
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

head

protected Node head

tail

protected Node tail

size

protected int size

Constructor Detail

NodeQueue

public NodeQueue()

Creates an empty queue.

Method Detail

size

public int size()

Description copied from interface: Queue

Returns the number of elements in the queue.

Specified by:

size in interface Queue

Returns:

number of elements in the queue.

isEmpty

public boolean isEmpty()

Description copied from interface: Queue

Returns whether the queue is empty.

Specified by:

isEmpty in interface Queue

Returns:

true if the queue is empty, false otherwise.

enqueue

public void enqueue(Object obj)

Description copied from interface: Queue

Inserts an element at the rear of the queue.

Specified by:

enqueue in interface Queue

Parameters:

obj - new element to be inserted.

front

public Object front()
             throws EmptyQueueException

Description copied from interface: Queue

Inspects the element at the front of the queue.

Specified by:

front in interface Queue

Returns:

element at the front of the queue.

Throws:

EmptyQueueException - if the queue is empty.

dequeue

public Object dequeue()
               throws EmptyQueueException

Description copied from interface: Queue

Removes the element at the front of the queue.

Specified by:

dequeue in interface Queue

Returns:

element removed.

Throws:

EmptyQueueException - if the queue is empty.

toString

public String toString()