org.apache.lucene.index.sorter

Class EarlyTerminatingSortingCollector

java.lang.Object

org.apache.lucene.search.Collector

org.apache.lucene.index.sorter.EarlyTerminatingSortingCollector

public class EarlyTerminatingSortingCollector
extends Collector

A Collector that early terminates collection of documents on a per-segment basis, if the segment was sorted according to the given Sorter.

NOTE: the Collector detects sorted segments according to SortingMergePolicy, so it's best used in conjunction with it. Also, it collects up to a specified num docs from each segment, and therefore is mostly suitable for use in conjunction with collectors such as TopDocsCollector, and not e.g. TotalHitCountCollector.

NOTE: If you wrap a TopDocsCollector that sorts in the same order as the index order, the returned TopDocsCollector.topDocs() will be correct. However the total of hit count will be underestimated since not all matching documents will have been collected.

NOTE: This Collector uses Sorter.getID() to detect whether a segment was sorted with the same Sorter as the one given in EarlyTerminatingSortingCollector(Collector, Sorter, int). This has two implications:

• if Sorter.getID() is not implemented correctly and returns different identifiers for equivalent Sorters, this collector will not detect sorted segments,
• if you suddenly change the IndexWriter's SortingMergePolicy to sort according to another criterion and if both the old and the new Sorters have the same identifier, this Collector will incorrectly detect sorted segments.

WARNING: This API is experimental and might change in incompatible ways in the next release.

Field Summary

Fields

Modifier and Type	Field and Description
protected Collector	in
protected int	numDocsToCollect
protected boolean	segmentSorted
protected int	segmentTotalCollect
protected Sorter	sorter

Constructor Summary

Constructors

Constructor and Description
EarlyTerminatingSortingCollector(Collector in, Sorter sorter, int numDocsToCollect) Create a new EarlyTerminatingSortingCollector instance.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	acceptsDocsOutOfOrder()
void	collect(int doc)
void	setNextReader(AtomicReaderContext context)
void	setScorer(Scorer scorer)

Methods inherited from class java.lang.Object

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

Field Detail

in

protected final Collector in

sorter

protected final Sorter sorter

numDocsToCollect

protected final int numDocsToCollect

segmentTotalCollect

protected int segmentTotalCollect

segmentSorted

protected boolean segmentSorted

Constructor Detail

EarlyTerminatingSortingCollector

public EarlyTerminatingSortingCollector(Collector in,
                                Sorter sorter,
                                int numDocsToCollect)

Create a new EarlyTerminatingSortingCollector instance.

Parameters:

in - the collector to wrap

sorter - the same sorter as the one which is used by IndexWriter's SortingMergePolicy

numDocsToCollect - the number of documents to collect on each segment. When wrapping a TopDocsCollector, this number should be the number of hits.

Method Detail

setScorer

public void setScorer(Scorer scorer)
               throws IOException

Specified by:

setScorer in class Collector

Throws:

IOException

collect

public void collect(int doc)
             throws IOException

Specified by:

collect in class Collector

Throws:

IOException

setNextReader

public void setNextReader(AtomicReaderContext context)
                   throws IOException

Specified by:

setNextReader in class Collector

Throws:

IOException

acceptsDocsOutOfOrder

public boolean acceptsDocsOutOfOrder()

Specified by:

acceptsDocsOutOfOrder in class Collector