fi.uef.cs.tra

Class PriorityQueue<E>

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractQueue<E>

java.util.PriorityQueue<E>

fi.uef.cs.tra.PriorityQueue<E>

All Implemented Interfaces:

java.io.Serializable, java.lang.Iterable<E>, java.util.Collection<E>, java.util.Queue<E>

public class PriorityQueue<E>
extends java.util.PriorityQueue<E>

PriorityQueue is a convenience extension of java.util.PriorityQueue for relocation. PriorityQueue arranges the elements according to their natural order. The elements must implement the interface java.util.Comparable or a java.util.Comparator must be provided for the constructor. For example

   PriorityQueue pq = new PriorityQueue();
   pq.add("foobar");
   pq.add("tra");
   pq.add("priorityqueue");
   pq.add("et cetera");
   
   String polled;
   while ((polled = pq.poll()) != null)
     System.out.println(polled);
 

would produce

  et cetera
  foobar
  priorityqueue
  tra
 

With Strings it is worth noting that the sorting is case sensitive so that Strings starting with capital letters take precedence.

See Also:

PriorityQueue, Serialized Form

Constructor Summary

Constructors

Constructor and Description
PriorityQueue() Creates a PriorityQueue with the default initial capacity (11) that orders its elements according to their natural ordering (using java.util.Comparable).
PriorityQueue(java.util.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 java.util.Comparable).
PriorityQueue(int initialCapacity, java.util.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(java.util.SortedSet<? extends E> c) Creates a PriorityQueue containing the elements in the specified collection.

Method Summary

Modifier and Type	Method and Description
boolean	add(E o)
void	clear()
java.util.Comparator<? super E>	comparator()
java.util.Iterator<E>	iterator()
E	poll()
boolean	remove(java.lang.Object o)
int	size()

Methods inherited from class java.util.PriorityQueue

contains, offer, peek, spliterator, toArray, toArray

Methods inherited from class java.util.AbstractQueue

addAll, element, remove

Methods inherited from class java.util.AbstractCollection

containsAll, isEmpty, removeAll, retainAll, toString

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Collection

containsAll, equals, hashCode, isEmpty, parallelStream, removeAll, removeIf, retainAll, stream

Methods inherited from interface java.lang.Iterable

forEach

Constructor Detail

PriorityQueue

public PriorityQueue()

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

PriorityQueue

public PriorityQueue(int initialCapacity)

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

Parameters:

initialCapacity - the initial capacity for this priority queue.

Throws:

java.lang.IllegalArgumentException - if initialCapacity is less than 1

PriorityQueue

public PriorityQueue(int initialCapacity,
                     java.util.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:

java.lang.IllegalArgumentException - if initialCapacity is less than 1

PriorityQueue

public PriorityQueue(java.util.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:

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

java.lang.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:

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

java.lang.NullPointerException - if c or any element within it is null

PriorityQueue

public PriorityQueue(java.util.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:

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

java.lang.NullPointerException - if c or any element within it is null

Method Detail

add

public boolean add(E o)

Specified by:

add in interface java.util.Collection<E>

Specified by:

add in interface java.util.Queue<E>

Overrides:

add in class java.util.PriorityQueue<E>

remove

public boolean remove(java.lang.Object o)

Specified by:

remove in interface java.util.Collection<E>

Overrides:

remove in class java.util.PriorityQueue<E>

iterator

public java.util.Iterator<E> iterator()

Specified by:

iterator in interface java.lang.Iterable<E>

Specified by:

iterator in interface java.util.Collection<E>

Overrides:

iterator in class java.util.PriorityQueue<E>

size

public int size()

Specified by:

size in interface java.util.Collection<E>

Overrides:

size in class java.util.PriorityQueue<E>

clear

public void clear()

Specified by:

clear in interface java.util.Collection<E>

Overrides:

clear in class java.util.PriorityQueue<E>

poll

public E poll()

Specified by:

poll in interface java.util.Queue<E>

Overrides:

poll in class java.util.PriorityQueue<E>

comparator

public java.util.Comparator<? super E> comparator()

Overrides:

comparator in class java.util.PriorityQueue<E>