org.rollerjm.graph
Class Dijkstra.PriorityQueue

java.lang.Object
  |
  +--org.rollerjm.graph.Dijkstra.PriorityQueue

Enclosing class:

Dijkstra

public class Dijkstra.PriorityQueue

extends java.lang.Object

Title: graphs

Description: inner class of Dijkstra used by the Dijkstra's algorithm to choose the shortest vertex (the one whose priority is the lowest !)

Copyright: Copyright (c) 2002

Company:

Version:

1.0

Author:

Jean-Michel Garnier

Nested Class Summary

(package private) class

Dijkstra.PriorityQueue.QueueElement Title: graphs

Field Summary

private java.util.TreeSet

queue the queue is implemented by a TreeSet because it includes a sort algorithm !

Constructor Summary

Dijkstra.PriorityQueue()

Method Summary

void	clear() Remove all the elements of the queue
java.lang.Object	dequeueLowestPriorityElement()
int	getSize()
void	insert(java.lang.Object element, int priority)
boolean	isEmpty()

Methods inherited from class java.lang.Object

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

Field Detail

queue

private java.util.TreeSet queue

the queue is implemented by a TreeSet because it includes a sort algorithm !

Constructor Detail

Dijkstra.PriorityQueue

public Dijkstra.PriorityQueue()

Method Detail

clear

public void clear()

Remove all the elements of the queue

isEmpty

public boolean isEmpty()

Returns:

true if the queue is empty

getSize

public int getSize()

Returns:

int the number of elements in the queue

insert

public void insert(java.lang.Object element,
                   int priority)

Parameters:

element - any object !

priority - should be >= 0

dequeueLowestPriorityElement

public java.lang.Object dequeueLowestPriorityElement()

Returns:

Object the element in the queue which has the lowest priority. Also removes it from the queue.