Package algs13

Class Queue<T>

java.lang.Object

algs13.Queue<T>

All Implemented Interfaces:

Iterable<T>

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

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 1.3 of Algorithms, 4th Edition by Robert Sedgewick and Kevin Wayne.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private class	Queue.ListIterator
private static class	Queue.Node<T>

Field Summary

Fields

Modifier and Type	Field	Description
private Queue.Node<T>	first
private Queue.Node<T>	last
private int	N

Constructor Summary

Constructors

Constructor	Description
Queue()	Create an empty queue.

Method Summary

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

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Field Details

N

private int N

first

private Queue.Node<T> first

last

private Queue.Node<T> last

Constructor Details

Queue

public Queue()

Create an empty queue.

Method Details

isEmpty

public boolean isEmpty()

Is the queue empty?

size

public int size()

Return the number of items in the queue.

peek

public T peek()

Return the item least recently added to the queue.

Throws:

NoSuchElementException - if queue is empty.

enqueue

public void enqueue(T item)

Add the item to the queue.

dequeue

public T dequeue()

Remove and return the item on the queue least recently added.

Throws:

NoSuchElementException - if queue is empty.

toString

public String toString()

Return string representation.

Overrides:

toString in class Object

check

private static <T> boolean check(Queue<T> that)

iterator

public Iterator<T> iterator()

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

Specified by:

iterator in interface Iterable<T>

toGraphviz

public void toGraphviz(String filename)

toGraphviz

private void toGraphviz(GraphvizBuilder gb,
 Queue.Node<T> prev,
 Queue.Node<T> n)

main

public static void main(String[] args)

A test client.