edu.uci.ics.jung.utils
Class MapBinaryHeap

java.lang.Object
  java.util.AbstractCollection
      edu.uci.ics.jung.utils.MapBinaryHeap

All Implemented Interfaces:

Iterable, Collection

public class MapBinaryHeap
extends AbstractCollection
implements Collection

An array-based binary heap implementation of a priority queue, which also provides efficient update() and contains operations. It contains extra infrastructure (a hash table) to keep track of the position of each element in the array; thus, if the key value of an element changes, it may be "resubmitted" to the heap via update so that the heap can reposition it efficiently, as necessary.

Author:

Joshua O'Madadhain

Constructor Summary

MapBinaryHeap()
Creates a MapBinaryHeap whose heap ordering will be based on the natural ordering of the elements, which must be Comparable.

MapBinaryHeap(Collection c)
Creates a MapBinaryHeap based on the specified collection whose heap ordering will be based on the natural ordering of the elements, which must be Comparable.

MapBinaryHeap(Collection c, Comparator comp)
Creates a MapBinaryHeap based on the specified collection whose heap ordering is based on the ordering of the elements specified by c.

MapBinaryHeap(Comparator comp)
Creates a MapBinaryHeap whose heap ordering is based on the ordering of the elements specified by c.

Method Summary

boolean	add(Object o) Inserts o into this collection.
void	clear()
boolean	contains(Object o)
boolean	isEmpty() Returns true if this collection contains no elements, and false otherwise.
Iterator	iterator() Returns an Iterator that does not support modification of the heap.
Object	peek() Returns the element at the top of the heap; does not alter the heap.
Object	pop() Removes the element at the top of this heap, and returns it.
boolean	remove(Object o) This data structure does not support the removal of arbitrary elements.
boolean	removeAll(Collection c) This data structure does not support the removal of arbitrary elements.
boolean	retainAll(Collection c) This data structure does not support the removal of arbitrary elements.
int	size() Returns the size of this heap.
void	update(Object o) Informs the heap that this object's internal key value has been updated, and that its place in the heap may need to be shifted (up or down).

Methods inherited from class java.util.AbstractCollection

addAll, containsAll, toArray, toArray, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Collection

addAll, containsAll, equals, hashCode, toArray, toArray

Constructor Detail

MapBinaryHeap

public MapBinaryHeap(Comparator comp)

Creates a MapBinaryHeap whose heap ordering is based on the ordering of the elements specified by c.

MapBinaryHeap

public MapBinaryHeap()

Creates a MapBinaryHeap whose heap ordering will be based on the natural ordering of the elements, which must be Comparable.

MapBinaryHeap

public MapBinaryHeap(Collection c)

Creates a MapBinaryHeap based on the specified collection whose heap ordering will be based on the natural ordering of the elements, which must be Comparable.

MapBinaryHeap

public MapBinaryHeap(Collection c,
                     Comparator comp)

Creates a MapBinaryHeap based on the specified collection whose heap ordering is based on the ordering of the elements specified by c.

Method Detail

clear

public void clear()

Specified by:

clear in interface Collection

Overrides:

clear in class AbstractCollection

See Also:

Collection.clear()

add

public boolean add(Object o)

Inserts o into this collection.

Specified by:

add in interface Collection

Overrides:

add in class AbstractCollection

isEmpty

public boolean isEmpty()

Returns true if this collection contains no elements, and false otherwise.

Specified by:

isEmpty in interface Collection

Overrides:

isEmpty in class AbstractCollection

peek

public Object peek()
            throws NoSuchElementException

Returns the element at the top of the heap; does not alter the heap.

Throws:

NoSuchElementException

pop

public Object pop()
           throws NoSuchElementException

Removes the element at the top of this heap, and returns it.

Throws:

NoSuchElementException

size

public int size()

Returns the size of this heap.

Specified by:

size in interface Collection

Specified by:

size in class AbstractCollection

update

public void update(Object o)

Informs the heap that this object's internal key value has been updated, and that its place in the heap may need to be shifted (up or down).

Parameters:

o -

contains

public boolean contains(Object o)

Specified by:

contains in interface Collection

Overrides:

contains in class AbstractCollection

See Also:

Collection.contains(java.lang.Object)

iterator

public Iterator iterator()

Returns an Iterator that does not support modification of the heap.

Specified by:

iterator in interface Iterable

Specified by:

iterator in interface Collection

Specified by:

iterator in class AbstractCollection

remove

public boolean remove(Object o)

This data structure does not support the removal of arbitrary elements.

Specified by:

remove in interface Collection

Overrides:

remove in class AbstractCollection

removeAll

public boolean removeAll(Collection c)

This data structure does not support the removal of arbitrary elements.

Specified by:

removeAll in interface Collection

Overrides:

removeAll in class AbstractCollection

retainAll

public boolean retainAll(Collection c)

This data structure does not support the removal of arbitrary elements.

Specified by:

retainAll in interface Collection

Overrides:

retainAll in class AbstractCollection