edu.umd.cs.jazz.util
Class ZPriorityQueue

java.lang.Object
  |
  +--edu.umd.cs.jazz.util.ZPriorityQueue

public class ZPriorityQueue

extends java.lang.Object

ZPriorityQueue is a heap based PriorityQueue that stores objects of type java.lang.Comparable. The default ordering is by maximum value.

Author:

Jesse Grosjean

QUEUE_MAXIMUM_ORDERING

public static final int QUEUE_MAXIMUM_ORDERING

See Also:

Constant Field Values

QUEUE_MINIMUM_ORDERING

public static final int QUEUE_MINIMUM_ORDERING

See Also:

Constant Field Values

ZPriorityQueue

public ZPriorityQueue()

Construct a new priority queue, ordering by maximum value.

ZPriorityQueue

public ZPriorityQueue(int aOrdering)

Construct a new priority queue.

Parameters:

aOrdering - determines the ordering of items stored in the queue. use ZPriorityQueue.QUEUE_MAXIMUM_ORDERING or ZPriorityQueue.QUEUE_MINIMUM_ORDERING

insert

public void insert(java.lang.Comparable aComparable)

Insert a new item into the queue.

first

public java.lang.Object first()

Return the first object in the queue. This will either be the maximum or minimum valued object as determined by the queue ordering. This operation does not remove the object from the queue.

extractFirst

public java.lang.Object extractFirst()

Return the first object in the queue. This will either be the maximum or minimum valued object as determined by the queue ordering. This operation removes the object from the queue.

size

public int size()

Return the number of items currently in the queue.

isEmpty

public boolean isEmpty()

Return true if the queue is empty.

elements

protected java.util.ArrayList elements()

parent

protected int parent(int index)

left

protected int left(int index)

right

protected int right(int index)

heapify

protected void heapify(int index)

exchange

protected void exchange(int a,
                        int b)

get

protected java.lang.Comparable get(int index)

set

protected void set(int index,
                   java.lang.Comparable aComparable)

expand

protected void expand()

contract

protected void contract()

isProposedOrderCorrect

protected boolean isProposedOrderCorrect(java.lang.Comparable aProposedFirst,
                                         java.lang.Comparable aProposedSecond)