ch.randelshofer.util
Class PriorityQueue

java.lang.Object
  java.util.AbstractCollection<E>
      java.util.AbstractList
          ch.randelshofer.util.PriorityQueue

All Implemented Interfaces:

java.io.Serializable, java.lang.Iterable, java.util.Collection, java.util.List

public class PriorityQueue
extends java.util.AbstractList
implements java.io.Serializable

JDCTechTips 2002-08-22. John Zukowski.

Author:

Werner Randelshofer

See Also:

Serialized Form

Field Summary

Fields inherited from class java.util.AbstractList

modCount

Constructor Summary

PriorityQueue()
Constructs an empty priority queue which supports the priorities 0 to 9 (10 distinct priorities).

PriorityQueue(java.util.Collection col)
Constructs a priority queue containing the elements of the specified collection, in the order they are returned by the collection'siterator.

PriorityQueue(java.util.Collection col, int count)
Constructs a priority queue containing the elements of the specified collection, in the order they are returned by the collection'siterator.

PriorityQueue(int count)
Constructs an empty priority queue which supports the specified count of priorities.

Method Summary

boolean	add(java.lang.Object element) Inserts an element to the priority queue using priority 0 (the lowest priority).
void	clear() Removes all of the elements from this priority queue.
java.lang.Object	get(int index) Returns the element at the specified position in this priority queue.
java.lang.Object	getFirst() Returns the first element in this priority queue.
int	getPriorityCount() Returns the priority count.
void	insert(java.lang.Object element, int priority) Inserts an element to the priority queue using the specified priority.
java.util.Iterator	iterator() Returns an iterator of the elements in this priority queue (elements with higher priorities first).
java.lang.Object	removeFirst() Returns the first element in this priority queue and returns it.
int	size() Returns the number of elements in this priority queue.
java.lang.String	toString() Returns a string representation of this collection.

Methods inherited from class java.util.AbstractList

add, addAll, equals, hashCode, indexOf, lastIndexOf, listIterator, listIterator, remove, removeRange, set, subList

Methods inherited from class java.util.AbstractCollection

addAll, contains, containsAll, isEmpty, remove, removeAll, retainAll, toArray, toArray

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.List

addAll, contains, containsAll, isEmpty, remove, removeAll, retainAll, toArray, toArray

Constructor Detail

PriorityQueue

public PriorityQueue()

Constructs an empty priority queue which supports the priorities 0 to 9 (10 distinct priorities).

PriorityQueue

public PriorityQueue(java.util.Collection col)

Constructs a priority queue containing the elements of the specified collection, in the order they are returned by the collection'siterator. The created PriorityQueue supports the priorities 0 to 9 (10 distinct priorities). All elements are added using priority 0 (the lowest priority).

PriorityQueue

public PriorityQueue(int count)

Constructs an empty priority queue which supports the specified count of priorities.

PriorityQueue

public PriorityQueue(java.util.Collection col,
                     int count)

Constructs a priority queue containing the elements of the specified collection, in the order they are returned by the collection'siterator. The created PriorityQueue supports count distinct priorities. All elements are added using priority 0 (the lowest priority).

Throws:

java.lang.IllegalArgumentException - if the specified priority count is is out of range count < 0.

Method Detail

add

public boolean add(java.lang.Object element)

Inserts an element to the priority queue using priority 0 (the lowest priority).

Specified by:

add in interface java.util.Collection

Specified by:

add in interface java.util.List

Overrides:

add in class java.util.AbstractList

getPriorityCount

public int getPriorityCount()

Returns the priority count.

insert

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

Inserts an element to the priority queue using the specified priority.

Throws:

java.lang.IllegalArgumentException - if the specified priority is is out of range (priority < 0 || priority >= getPriorityCount()).

getFirst

public java.lang.Object getFirst()

Returns the first element in this priority queue. Elements are returned highest priority first.

get

public java.lang.Object get(int index)

Returns the element at the specified position in this priority queue. The elements are ordered by priority.

Specified by:

get in interface java.util.List

Specified by:

get in class java.util.AbstractList

Throws:

java.lang.IndexOutOfBoundsException - if the specified index is is out of range (index < 0 || index >= size()).

clear

public void clear()

Removes all of the elements from this priority queue.

Specified by:

clear in interface java.util.Collection

Specified by:

clear in interface java.util.List

Overrides:

clear in class java.util.AbstractList

removeFirst

public java.lang.Object removeFirst()

Returns the first element in this priority queue and returns it. Elements are returned highest priority first.

size

public int size()

Returns the number of elements in this priority queue.

Specified by:

size in interface java.util.Collection

Specified by:

size in interface java.util.List

Specified by:

size in class java.util.AbstractCollection

iterator

public java.util.Iterator iterator()

Returns an iterator of the elements in this priority queue (elements with higher priorities first).

Specified by:

iterator in interface java.lang.Iterable

Specified by:

iterator in interface java.util.Collection

Specified by:

iterator in interface java.util.List

Overrides:

iterator in class java.util.AbstractList

toString

public java.lang.String toString()

Returns a string representation of this collection. The string representation consists of a list of the collection's elements in the order they are returned by its iterator, enclosed in square brackets ("[]"). Adjacent elements are separated by the characters ", " (comma and space). Elements are converted to strings as by String.valueOf(Object).

Overrides:

toString in class java.util.AbstractCollection