fi.joensuu.cs.tra
Class PriorityQueue<E>

java.lang.Object
  java.util.AbstractCollection
      java.util.AbstractQueue
          java.util.PriorityQueue
              fi.joensuu.cs.tra.PriorityQueue

All Implemented Interfaces:

Collection, Iterable, Queue, Serializable

public class PriorityQueue<E>

extends PriorityQueue<E>

PriorityQueue is a convenience extension of java.util.PriorityQueue for relocation.

See Also:

PriorityQueue, Serialized Form

Constructor Summary

PriorityQueue()
Creates a PriorityQueue with the default initial capacity (11) that orders its elements according to their natural ordering (using Comparable).

PriorityQueue(Collection<? extends E> c)
Creates a PriorityQueue containing the elements in the specified collection.

PriorityQueue(int initialCapacity)
Creates a PriorityQueue with the specified initial capacity that orders its elements according to their natural ordering (using Comparable).

PriorityQueue(int initialCapacity, Comparator<? super E> comparator)
Creates a PriorityQueue with the specified initial capacity that orders its elements according to the specified comparator.

PriorityQueue(PriorityQueue<? extends E> c)
Creates a PriorityQueue containing the elements in the specified collection.

PriorityQueue(SortedSet<? extends E> c)
Creates a PriorityQueue containing the elements in the specified collection.

Method Summary

boolean	add(E o) Adds the specified element to this queue.
void	clear() Remove all elements from the priority queue.
Comparator<? super E>	comparator() Returns the comparator used to order this collection, or null if this collection is sorted according to its elements natural ordering (using Comparable).
Iterator<E>	iterator() Returns an iterator over the elements in this queue.
E	poll() Retrieves and removes the head of this queue, or null if this queue is empty.
boolean	remove(Object o) Removes a single instance of the specified element from this collection, if it is present (optional operation).
int	size() Returns the number of elements in this collection.

Methods inherited from class java.util.PriorityQueue

offer, peek

Methods inherited from class java.util.AbstractQueue

addAll, element, remove

Methods inherited from class java.util.AbstractCollection

contains, containsAll, isEmpty, removeAll, retainAll, 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.Queue

element, remove

Methods inherited from interface java.util.Collection

addAll, contains, containsAll, equals, hashCode, isEmpty, removeAll, retainAll, toArray, toArray

Constructor Detail

PriorityQueue

public PriorityQueue()

Creates a PriorityQueue with the default initial capacity (11) that orders its elements according to their natural ordering (using Comparable).

PriorityQueue

public PriorityQueue(int initialCapacity)

Creates a PriorityQueue with the specified initial capacity that orders its elements according to their natural ordering (using Comparable).

Parameters:

initialCapacity - the initial capacity for this priority queue.

Throws:

IllegalArgumentException - if initialCapacity is less than 1

PriorityQueue

public PriorityQueue(int initialCapacity,
                     Comparator<? super E> comparator)

Creates a PriorityQueue with the specified initial capacity that orders its elements according to the specified comparator.

Parameters:

initialCapacity - the initial capacity for this priority queue.

comparator - the comparator used to order this priority queue. If null then the order depends on the elements' natural ordering.

Throws:

IllegalArgumentException - if initialCapacity is less than 1

PriorityQueue

public PriorityQueue(Collection<? extends E> c)

Creates a PriorityQueue containing the elements in the specified collection. The priority queue has an initial capacity of 110% of the size of the specified collection or 1 if the collection is empty. If the specified collection is an instance of a java.util.SortedSet or is another PriorityQueue, the priority queue will be sorted according to the same comparator, or according to its elements' natural order if the collection is sorted according to its elements' natural order. Otherwise, the priority queue is ordered according to its elements' natural order.

Parameters:

c - the collection whose elements are to be placed into this priority queue.

Throws:

ClassCastException - if elements of the specified collection cannot be compared to one another according to the priority queue's ordering.

NullPointerException - if c or any element within it is null

PriorityQueue

public PriorityQueue(PriorityQueue<? extends E> c)

Creates a PriorityQueue containing the elements in the specified collection. The priority queue has an initial capacity of 110% of the size of the specified collection or 1 if the collection is empty. This priority queue will be sorted according to the same comparator as the given collection, or according to its elements' natural order if the collection is sorted according to its elements' natural order.

Parameters:

c - the collection whose elements are to be placed into this priority queue.

Throws:

ClassCastException - if elements of the specified collection cannot be compared to one another according to the priority queue's ordering.

NullPointerException - if c or any element within it is null

PriorityQueue

public PriorityQueue(SortedSet<? extends E> c)

Creates a PriorityQueue containing the elements in the specified collection. The priority queue has an initial capacity of 110% of the size of the specified collection or 1 if the collection is empty. This priority queue will be sorted according to the same comparator as the given collection, or according to its elements' natural order if the collection is sorted according to its elements' natural order.

Parameters:

c - the collection whose elements are to be placed into this priority queue.

Throws:

ClassCastException - if elements of the specified collection cannot be compared to one another according to the priority queue's ordering.

NullPointerException - if c or any element within it is null

Method Detail

add

public boolean add(E o)

Description copied from class: java.util.PriorityQueue

Adds the specified element to this queue.

Specified by:

add in interface Collection

Overrides:

add in class PriorityQueue

Parameters:

o - the element

Returns:

true (as per the general contract of Collection.add).

remove

public boolean remove(Object o)

Description copied from class: java.util.AbstractCollection

Removes a single instance of the specified element from this collection, if it is present (optional operation). More formally, removes an element e such that (o==null ? e==null : o.equals(e)), if the collection contains one or more such elements. Returns true if the collection contained the specified element (or equivalently, if the collection changed as a result of the call).

This implementation iterates over the collection looking for the specified element. If it finds the element, it removes the element from the collection using the iterator's remove method.

Note that this implementation throws an UnsupportedOperationException if the iterator returned by this collection's iterator method does not implement the remove method and this collection contains the specified object.

Specified by:

remove in interface Collection

Overrides:

remove in class PriorityQueue

Parameters:

o - element to be removed from this collection, if present.

Returns:

true if the collection contained the specified element.

iterator

public Iterator<E> iterator()

Description copied from class: java.util.PriorityQueue

Returns an iterator over the elements in this queue. The iterator does not return the elements in any particular order.

Specified by:

iterator in interface Collection

Overrides:

iterator in class PriorityQueue

Returns:

an iterator over the elements in this queue.

size

public int size()

Description copied from class: java.util.AbstractCollection

Returns the number of elements in this collection. If the collection contains more than Integer.MAX_VALUE elements, returns Integer.MAX_VALUE.

Specified by:

size in interface Collection

Overrides:

size in class PriorityQueue

Returns:

the number of elements in this collection.

clear

public void clear()

Description copied from class: java.util.PriorityQueue

Remove all elements from the priority queue.

Specified by:

clear in interface Collection

Overrides:

clear in class PriorityQueue

poll

public E poll()

Description copied from interface: java.util.Queue

Retrieves and removes the head of this queue, or null if this queue is empty.

Specified by:

poll in interface Queue

Overrides:

poll in class PriorityQueue

Returns:

the head of this queue, or null if this queue is empty.

comparator

public Comparator<? super E> comparator()

Description copied from class: java.util.PriorityQueue

Returns the comparator used to order this collection, or null if this collection is sorted according to its elements natural ordering (using Comparable).

Overrides:

comparator in class PriorityQueue

Returns:

the comparator used to order this collection, or null if this collection is sorted according to its elements natural ordering.