salvo.jesus.util

Class Heap

java.lang.Object

salvo.jesus.util.Heap

All Implemented Interfaces:

Serializable

public class Heap
extends Object
implements Serializable

The Heap class implements a heap data structure, also called a priority queue.

Author:

Jesus M. Salvo Jr.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
Heap() Creates an instance of a Heap.
Heap(HeapNodeComparator comparator) Creates an instance of a Heap, with a specified HeapNodeComparator.

Method Summary

Modifier and Type	Method and Description
void	clear() Clears the heap, removing all nodes in the heap.
HeapNode	contains(Object object, Comparator heapnodeobjectcomparator) Determines if the given object is encapsulated by one of the nodes in the heap.
void	insert(HeapNode node) Add a new item into the heap
boolean	isEmpty() Checks if the heap is empty
HeapNode	remove() Remove the item with the highest priority from the heap.
void	setPriority(HeapNode node, double priority) Sets the priority of a specific node in the heap, thereby also forcing to fixup the heap to satisfy the heap condition.
String	toString() Returns a String representation of the Heap.

Methods inherited from class java.lang.Object

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

Constructor Detail

Heap

public Heap()

Creates an instance of a Heap. Using this constructor will make use of the default HeapNodeComparator. The HeapNodeConstructor created will have priorities sorted in such a way that priorities that are numerically higher are at the top of the heap.

Heap

public Heap(HeapNodeComparator comparator)

Creates an instance of a Heap, with a specified HeapNodeComparator. This way, you can control if nodes with numerically higher priorities are at the top or bottom of the heap. To have nodes with numerically lower priorities at the top of the heap, create a HeapNodeComparator with a constructor parameter that is > 0.

Parameters:

comapartor - The HeapNodeComparator object to be used in comparing the priorities of the nodes of the heap.

Method Detail

insert

public void insert(HeapNode node)

Add a new item into the heap

remove

public HeapNode remove()

Remove the item with the highest priority from the heap.

setPriority

public void setPriority(HeapNode node,
                        double priority)

Sets the priority of a specific node in the heap, thereby also forcing to fixup the heap to satisfy the heap condition.

Parameters:

node - The HeapNode object whose priority is to be changed

priority - The new priority that will be assigned to the heapnode.

clear

public void clear()

Clears the heap, removing all nodes in the heap.

isEmpty

public boolean isEmpty()

Checks if the heap is empty

contains

public HeapNode contains(Object object,
                         Comparator heapnodeobjectcomparator)

Determines if the given object is encapsulated by one of the nodes in the heap. If it is, then the HeapNode encapsulating the object is returned.

toString

public String toString()

Returns a String representation of the Heap.

Overrides:

toString in class Object