org.jboss.util
Class Heap

java.lang.Object
  |
  +--org.jboss.util.Heap

public class Heap

extends java.lang.Object

Data structure that mantains data in a ordered binary tree; each node is greater (smaller) or equal than its 2 sub-nodes, for all the hierarchy.

Elements of this data structure should either implement Comparable, or a Comparator should be given as argument to the constructor.

Version:

$Revision: 1.2 $

Author:

Simone Bordet (simone.bordet@compaq.com)

Constructor Summary

Heap()
Creates a new Heap whose elements inserted implement the Comparable interface.

Heap(java.util.Comparator comparator)
Creates a new Heap whose elements are compared using the given Comparator.

Method Summary

void	clear() Empties this heap
protected int	compare(java.lang.Object o1, java.lang.Object o2) Compares the given objects using the comparator, if available, or considering them Comparable objects.
java.lang.Object	extract() Removes and returns the least element of this heap.
void	insert(java.lang.Object obj) Inserts the given element in this heap.
protected int	left(int index) Returns the left child index of index.
protected int	parent(int index) Returns the parent index of index.
java.lang.Object	peek() Returns, without removing it, the least element of this heap.
protected int	right(int index) Returns the right child index of index.

Methods inherited from class java.lang.Object

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

Constructor Detail

Heap

public Heap()

Creates a new Heap whose elements inserted implement the Comparable interface.

Heap

public Heap(java.util.Comparator comparator)

Creates a new Heap whose elements are compared using the given Comparator.

Method Detail

insert

public void insert(java.lang.Object obj)

Inserts the given element in this heap.

See Also:

extract()

extract

public java.lang.Object extract()

Removes and returns the least element of this heap.

See Also:

insert(java.lang.Object), peek()

peek

public java.lang.Object peek()

Returns, without removing it, the least element of this heap.

See Also:

extract()

clear

public void clear()

Empties this heap

compare

protected int compare(java.lang.Object o1,
                      java.lang.Object o2)

Compares the given objects using the comparator, if available, or considering them Comparable objects.

Throws:

java.lang.ClassCastException - if nor the comparator is given and nor both objects implements the Comparable interface

parent

protected int parent(int index)

Returns the parent index of index.

left

protected int left(int index)

Returns the left child index of index.

right

protected int right(int index)

Returns the right child index of index.