org.apache.lucene.search.grouping.function

Class FunctionAllGroupHeadsCollector

java.lang.Object

org.apache.lucene.search.SimpleCollector

org.apache.lucene.search.grouping.AbstractAllGroupHeadsCollector<FunctionAllGroupHeadsCollector.GroupHead>

org.apache.lucene.search.grouping.function.FunctionAllGroupHeadsCollector

All Implemented Interfaces:

Collector, LeafCollector

public class FunctionAllGroupHeadsCollector
extends AbstractAllGroupHeadsCollector<FunctionAllGroupHeadsCollector.GroupHead>

An implementation of AbstractAllGroupHeadsCollector for retrieving the most relevant groups when grouping by ValueSource.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	FunctionAllGroupHeadsCollector.GroupHead Holds current head document for a single group.

Nested classes/interfaces inherited from class org.apache.lucene.search.grouping.AbstractAllGroupHeadsCollector

AbstractAllGroupHeadsCollector.TemporalResult

Field Summary

Fields inherited from class org.apache.lucene.search.grouping.AbstractAllGroupHeadsCollector

compIDXEnd, reversed, temporalResult

Constructor Summary

Constructors

Constructor and Description
FunctionAllGroupHeadsCollector(ValueSource groupBy, Map<?,?> vsContext, Sort sortWithinGroup) Constructs a FunctionAllGroupHeadsCollector instance.

Method Summary

Modifier and Type	Method and Description
protected void	doSetNextReader(LeafReaderContext context) This method is called before collecting context.
protected Collection<FunctionAllGroupHeadsCollector.GroupHead>	getCollectedGroupHeads() Returns the collected group heads.
boolean	needsScores() Indicates if document scores are needed by this collector.
protected void	retrieveGroupHeadAndAddIfNotExist(int doc) Returns the group head and puts it into AbstractAllGroupHeadsCollector.temporalResult.
void	setScorer(Scorer scorer) Called before successive calls to LeafCollector.collect(int).

Methods inherited from class org.apache.lucene.search.grouping.AbstractAllGroupHeadsCollector

collect, groupHeadsSize, retrieveGroupHeads, retrieveGroupHeads

Methods inherited from class org.apache.lucene.search.SimpleCollector

getLeafCollector

Methods inherited from class java.lang.Object

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

Constructor Detail

FunctionAllGroupHeadsCollector

public FunctionAllGroupHeadsCollector(ValueSource groupBy,
                                      Map<?,?> vsContext,
                                      Sort sortWithinGroup)

Constructs a FunctionAllGroupHeadsCollector instance.

Parameters:

groupBy - The ValueSource to group by

vsContext - The ValueSource context

sortWithinGroup - The sort within a group

Method Detail

retrieveGroupHeadAndAddIfNotExist

protected void retrieveGroupHeadAndAddIfNotExist(int doc)
                                          throws IOException

Description copied from class: AbstractAllGroupHeadsCollector

Returns the group head and puts it into AbstractAllGroupHeadsCollector.temporalResult. If the group head wasn't encountered before then it will be added to the collected group heads.

The AbstractAllGroupHeadsCollector.TemporalResult.stop property will be true if the group head wasn't encountered before otherwise false.

Specified by:

retrieveGroupHeadAndAddIfNotExist in class AbstractAllGroupHeadsCollector<FunctionAllGroupHeadsCollector.GroupHead>

Parameters:

doc - The document to retrieve the group head for.

Throws:

IOException - If I/O related errors occur

getCollectedGroupHeads

protected Collection<FunctionAllGroupHeadsCollector.GroupHead> getCollectedGroupHeads()

Description copied from class: AbstractAllGroupHeadsCollector

Returns the collected group heads. Subsequent calls should return the same group heads.

Specified by:

getCollectedGroupHeads in class AbstractAllGroupHeadsCollector<FunctionAllGroupHeadsCollector.GroupHead>

Returns:

the collected group heads

setScorer

public void setScorer(Scorer scorer)
               throws IOException

Description copied from interface: LeafCollector

Called before successive calls to LeafCollector.collect(int). Implementations that need the score of the current document (passed-in to LeafCollector.collect(int)), should save the passed-in Scorer and call scorer.score() when needed.

Specified by:

setScorer in interface LeafCollector

Overrides:

setScorer in class SimpleCollector

Throws:

IOException

doSetNextReader

protected void doSetNextReader(LeafReaderContext context)
                        throws IOException

Description copied from class: SimpleCollector

This method is called before collecting context.

Overrides:

doSetNextReader in class SimpleCollector

Throws:

IOException

needsScores

public boolean needsScores()

Description copied from interface: Collector

Indicates if document scores are needed by this collector.

Returns:

true if scores are needed.