edu.princeton.cs.introcs

Class Queue<Item>

java.lang.Object

edu.princeton.cs.introcs.Queue<Item>

All Implemented Interfaces:

Iterable<Item>

public class Queue<Item>
extends Object
implements Iterable<Item>

The Queue class represents a first-in-first-out (FIFO) queue of generic items. It supports the usual enqueue and dequeue operations, along with methods for peeking at the top item, testing if the queue is empty, and iterating through the items in FIFO order.

All queue operations except iteration are constant time.

For additional documentation, see Section 4.3 of Introduction to Programming in Java: An Interdisciplinary Approach by Robert Sedgewick and Kevin Wayne.

Constructor Summary

Constructors

Constructor and Description
Queue() Create an empty queue.

Method Summary

Methods

Modifier and Type	Method and Description
Item	dequeue() Remove and return the item on the queue least recently added.
void	enqueue(Item item) Add the item to the queue.
boolean	isEmpty() Is the queue empty?
Iterator<Item>	iterator() Return an iterator that iterates over the items on the queue in FIFO order.
int	length() Return the number of items in the queue.
static void	main(String[] args) A test client.
Item	peek() Return the item least recently added to the queue.
int	size() Return the number of items in the queue.
String	toString() Return string representation.

Methods inherited from class java.lang.Object

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

Constructor Detail

Queue

public Queue()

Create an empty queue.

Method Detail

isEmpty

public boolean isEmpty()

Is the queue empty?

size

public int size()

Return the number of items in the queue.

length

public int length()

Return the number of items in the queue.

peek

public Item peek()

Return the item least recently added to the queue. Throw an exception if the queue is empty.

enqueue

public void enqueue(Item item)

Add the item to the queue.

dequeue

public Item dequeue()

Remove and return the item on the queue least recently added. Throw an exception if the queue is empty.

toString

public String toString()

Return string representation.

Overrides:

toString in class Object

iterator

public Iterator<Item> iterator()

Return an iterator that iterates over the items on the queue in FIFO order.

Specified by:

iterator in interface Iterable<Item>

main

public static void main(String[] args)

A test client.