Class PriorityQueue<T>

A PriorityQueue<T> holds elements on a priority heap, which orders the elements according to their natural order or according to the comparator specified at construction time. If the queue uses natural ordering, only elements that are comparable are permitted to be inserted into the queue.

The least element of the specified ordering is stored at the head of the queue and the greatest element is stored at the tail of the queue.

A PriorityQueue<T> is not synchronized.

Inheritance

System.Object

PriorityQueue<T>

Namespace: Lucene.Net.Support

Assembly: Lucene.Net.dll

Syntax

public class PriorityQueue<T> : ICollection<T> where T : class

Type Parameters

Name	Description
T	Type of elements

Constructors

| Improve this Doc View Source

PriorityQueue()

Constructs a priority queue with an initial capacity of 11 and natural ordering.

Declaration

public PriorityQueue()

| Improve this Doc View Source

PriorityQueue(ICollection<T>)

Creates a PriorityQueue<T> containing the elements in the specified collection. If the specified collection is an instance of a , TreeSet<T>, or is another PriorityQueue<T>, this priority queue will be ordered according to the same ordering. Otherwise, this priority queue will be ordered according to the natural ordering of its elements.

Declaration

public PriorityQueue(ICollection<T> collection)

Parameters

Type	Name	Description
ICollection<T>	collection	collection to be inserted into priority queue

| Improve this Doc View Source

PriorityQueue(IComparer<T>)

Constructs a priority queue with the specified capacity and comparer.

Declaration

public PriorityQueue(IComparer<T> comparer)

Parameters

Type	Name	Description
IComparer<T>	comparer	The that will be used to order this priority queue. If `null`, the natural ordering of the elements will be used.

| Improve this Doc View Source

PriorityQueue(PriorityQueue<T>)

Creates a PriorityQueue<T> containing the elements in the specified priority queue. This priority queue will be ordered according to the same ordering as the given priority queue.

Declaration

public PriorityQueue(PriorityQueue<T> collection)

Parameters

Type	Name	Description
PriorityQueue<T>	collection	the priority queue whose elements are to be placed into this priority queue

| Improve this Doc View Source

PriorityQueue(TreeSet<T>)

Creates a PriorityQueue<T> containing the elements in the specified TreeSet<T>. This priority queue will be ordered according to the same ordering as the given TreeSet<T>.

The constructed priority queue has the initial capacity of 110% of the size of the sorted set. The priority queue will have the same comparator as the sorted set.

Declaration

public PriorityQueue(TreeSet<T> collection)

Parameters

Type	Name	Description
TreeSet<T>	collection	the sorted set whose elements are to be placed into this priority queue

| Improve this Doc View Source

PriorityQueue(SortedSet<T>)

Creates a PriorityQueue<T> containing the elements in the specified . This priority queue will be ordered according to the same ordering as the given .

The constructed priority queue has the initial capacity of 110% of the size of the sorted set. The priority queue will have the same comparator as the sorted set.

Declaration

public PriorityQueue(SortedSet<T> collection)

Parameters

Type	Name	Description
SortedSet<T>	collection	the sorted set whose elements are to be placed into this priority queue

| Improve this Doc View Source

PriorityQueue(Int32)

Constructs a priority queue with the specified capacity and natural ordering.

Declaration

public PriorityQueue(int initialCapacity)

Parameters

Type	Name	Description
System.Int32	initialCapacity	initial capacity

| Improve this Doc View Source

PriorityQueue(Int32, IComparer<T>)

Creates a PriorityQueue<T> with the specified initial capacity that orders its elements according to the specified comparer.

Declaration

public PriorityQueue(int initialCapacity, IComparer<T> comparer)

Parameters

Type	Name	Description
System.Int32	initialCapacity	the initial capacity for this priority queue
IComparer<T>	comparer	The that will be used to order this priority queue. If `null`, the natural ordering of the elements will be used.

Properties

| Improve this Doc View Source

Comparer

Gets the used to order the elements in this queue, or Lucene.Net.Util.ArrayUtil.NaturalComparer`1 if this queue is sorted according to the natural ordering of its elements.

Declaration

public virtual IComparer<T> Comparer { get; }

Property Value

Type	Description
IComparer<T>

| Improve this Doc View Source

Count

Gets the size of the priority queue. If the size of the queue is greater than the , then it returns .

Declaration

public virtual int Count { get; }

Property Value

Type	Description
System.Int32

| Improve this Doc View Source

IsReadOnly

Gets a value indicating whether the collection is read-only.

Declaration

public virtual bool IsReadOnly { get; }

Property Value

Type	Description
System.Boolean

Remarks

For priority queue this property returns false.

Methods

| Improve this Doc View Source

Add(T)

Adds the specified object to the priority queue.

Declaration

public virtual void Add(T item)

Parameters

Type	Name	Description
T	item	the object to be added.

| Improve this Doc View Source

AddAll(ICollection<T>)

Declaration

public virtual bool AddAll(ICollection<T> collection)

Parameters

Type	Name	Description
ICollection<T>	collection

Returns

Type	Description
System.Boolean

| Improve this Doc View Source

Clear()

Removes all of the elements from this priority queue.

Declaration

public virtual void Clear()

| Improve this Doc View Source

Contains(T)

Returns true if this queue contains the specified element. More formally, returns true if and only if this queue contains at least one element item such that o.Equals(item).

Declaration

public virtual bool Contains(T item)

Parameters

Type	Name	Description
T	item	The object to locate in the priority queue

Returns

Type	Description
System.Boolean	`true` if item is found in the priority queue; otherwise, `false.`

| Improve this Doc View Source

CopyTo(T[], Int32)

Copies the elements of the priority queue to an Array, starting at a particular Array index.

Declaration

public virtual void CopyTo(T[] array, int arrayIndex)

Parameters

Type	Name	Description
T[]	array	The one-dimensional Array that is the destination of the elements copied from the priority queue. The Array must have zero-based indexing.
System.Int32	arrayIndex	The zero-based index in array at which copying begins.

Remarks

It is not guaranteed that items will be copied in the sorted order.

| Improve this Doc View Source

Element()

Retrieves, but does not remove, the head of this queue. This method differs from Peek() only in that it throws an exception if this queue is empty.

This implementation returns the result of Peek() unless the queue is empty.

Declaration

public virtual T Element()

Returns

Type	Description
T	the head of this queue

| Improve this Doc View Source

GetEnumerator()

Gets the enumerator of the priority queue, which will not return elements in any specified ordering.

Declaration

public virtual IEnumerator<T> GetEnumerator()

Returns

Type	Description
IEnumerator<T>	The enumerator of the priority queue.

Remarks

Returned enumerator does not iterate elements in sorted order.

| Improve this Doc View Source

Offer(T)

Inserts the specified element into this priority queue.

Declaration

public virtual bool Offer(T item)

Parameters

Type	Name	Description
T	item	the element to add to the priority queue.

Returns

Type	Description
System.Boolean	always `true`

| Improve this Doc View Source

Peek()

Gets but does not remove the head of the queue.

Declaration

public virtual T Peek()

Returns

Type	Description
T	the head of the queue or null if the queue is empty.

| Improve this Doc View Source

Poll()

Gets and removes the head of the queue.

Declaration

public virtual T Poll()

Returns

Type	Description
T	the head of the queue or null if the queue is empty.

| Improve this Doc View Source

Remove()

Retrieves and removes the head of this queue. This method differs from Poll() only in that it throws an exception if this queue is empty.

This implementation returns the result of Poll() unless the queue is empty.

Declaration

public virtual T Remove()

Returns

Type	Description
T	the head of this queue

| Improve this Doc View Source

Remove(T)

Removes the specified object from the priority queue.

Declaration

public virtual bool Remove(T item)

Parameters

Type	Name	Description
T	item	the object to be removed.

Returns

Type	Description
System.Boolean	`true` if the object was in the priority queue, `false` if the object