org.apache.lucene.search
Class FieldSortedHitQueue

java.lang.Object
  org.apache.lucene.util.PriorityQueue
      org.apache.lucene.search.FieldSortedHitQueue

public class FieldSortedHitQueue
extends PriorityQueue

Expert: A hit queue for sorting by hits by terms in more than one field. Uses FieldCache.DEFAULT for maintaining internal term lookup tables.

Created: Dec 8, 2003 12:56:03 PM

Since:

lucene 1.4

Version:

$Id: FieldSortedHitQueue.java 695514 2008-09-15 15:42:11Z otis $

See Also:

Searcher.search(Query,Filter,int,Sort), FieldCache

Field Summary

protected ScoreDocComparator[]	comparators Stores a comparator corresponding to each field being sorted by
protected SortField[]	fields Stores the sort criteria being used.
protected float	maxscore Stores the maximum score value encountered, needed for normalizing.

Fields inherited from class org.apache.lucene.util.PriorityQueue

heap

Constructor Summary

FieldSortedHitQueue(IndexReader reader, SortField[] fields, int size)
Creates a hit queue sorted by the given list of fields.

Method Summary

float	getMaxScore() returns the maximum score encountered by elements inserted via insert()
boolean	insert(FieldDoc fdoc)
boolean	insert(Object fdoc) Adds element to the PriorityQueue in log(size) time if either the PriorityQueue is not full, or not lessThan(element, top()).
Object	insertWithOverflow(Object element) insertWithOverflow() is the same as insert() except its return value: it returns the object (if any) that was dropped off the heap because it was full.
protected boolean	lessThan(Object a, Object b) Returns whether a is less relevant than b.

Methods inherited from class org.apache.lucene.util.PriorityQueue

adjustTop, clear, initialize, pop, put, size, top

Methods inherited from class java.lang.Object

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

Field Detail

comparators

protected ScoreDocComparator[] comparators

Stores a comparator corresponding to each field being sorted by

fields

protected SortField[] fields

Stores the sort criteria being used.

maxscore

protected float maxscore

Stores the maximum score value encountered, needed for normalizing.

Constructor Detail

FieldSortedHitQueue

public FieldSortedHitQueue(IndexReader reader,
                           SortField[] fields,
                           int size)
                    throws IOException

Creates a hit queue sorted by the given list of fields.

Parameters:

reader - Index to use.

fields - Fieldable names, in priority order (highest priority first). Cannot be null or empty.

size - The number of hits to retain. Must be greater than zero.

Throws:

IOException

Method Detail

getMaxScore

public float getMaxScore()

returns the maximum score encountered by elements inserted via insert()

insert

public boolean insert(FieldDoc fdoc)

insert

public boolean insert(Object fdoc)

Description copied from class: PriorityQueue

Adds element to the PriorityQueue in log(size) time if either the PriorityQueue is not full, or not lessThan(element, top()).

Overrides:

insert in class PriorityQueue

Returns:

true if element is added, false otherwise.

insertWithOverflow

public Object insertWithOverflow(Object element)

Description copied from class: PriorityQueue

insertWithOverflow() is the same as insert() except its return value: it returns the object (if any) that was dropped off the heap because it was full. This can be the given parameter (in case it is smaller than the full heap's minimum, and couldn't be added), or another object that was previously the smallest value in the heap and now has been replaced by a larger one, or null if the queue wasn't yet full with maxSize elements.

Overrides:

insertWithOverflow in class PriorityQueue

lessThan

protected boolean lessThan(Object a,
                           Object b)

Returns whether a is less relevant than b.

Specified by:

lessThan in class PriorityQueue

Parameters:

a - ScoreDoc

b - ScoreDoc

Returns:

true if document a should be sorted after document b.