org.apache.lucene.search.grouping

Class SecondPassGroupingCollector<T>

java.lang.Object

org.apache.lucene.search.SimpleCollector

org.apache.lucene.search.grouping.SecondPassGroupingCollector<T>

All Implemented Interfaces:

Collector, LeafCollector

Direct Known Subclasses:

FunctionSecondPassGroupingCollector, TermSecondPassGroupingCollector

public abstract class SecondPassGroupingCollector<T>
extends SimpleCollector

SecondPassGroupingCollector is the second of two passes necessary to collect grouped docs. This pass gathers the top N documents per top group computed from the first pass. Concrete subclasses define what a group is and how it is internally collected.

See org.apache.lucene.search.grouping for more details including a full code example.

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

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	SecondPassGroupingCollector.SearchGroupDocs<T>

Field Summary

Fields

Modifier and Type	Field and Description
protected SecondPassGroupingCollector.SearchGroupDocs<T>[]	groupDocs
protected Map<T,SecondPassGroupingCollector.SearchGroupDocs<T>>	groupMap

Constructor Summary

Constructors

Constructor and Description
SecondPassGroupingCollector(Collection<SearchGroup<T>> groups, Sort groupSort, Sort withinGroupSort, int maxDocsPerGroup, boolean getScores, boolean getMaxScores, boolean fillSortFields)

Method Summary

Modifier and Type	Method and Description
void	collect(int doc)
protected void	doSetNextReader(LeafReaderContext readerContext)
TopGroups<T>	getTopGroups(int withinGroupOffset)
boolean	needsScores()
protected abstract SecondPassGroupingCollector.SearchGroupDocs<T>	retrieveGroup(int doc) Returns the group the specified doc belongs to or null if no group could be retrieved.
void	setScorer(Scorer scorer)

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

Field Detail

groupMap

protected final Map<T,SecondPassGroupingCollector.SearchGroupDocs<T>> groupMap

groupDocs

protected SecondPassGroupingCollector.SearchGroupDocs<T>[] groupDocs

Constructor Detail

SecondPassGroupingCollector

public SecondPassGroupingCollector(Collection<SearchGroup<T>> groups,
                                   Sort groupSort,
                                   Sort withinGroupSort,
                                   int maxDocsPerGroup,
                                   boolean getScores,
                                   boolean getMaxScores,
                                   boolean fillSortFields)
                            throws IOException

Throws:

IOException

Method Detail

needsScores

public boolean needsScores()

setScorer

public void setScorer(Scorer scorer)
               throws IOException

Specified by:

setScorer in interface LeafCollector

Overrides:

setScorer in class SimpleCollector

Throws:

IOException

collect

public void collect(int doc)
             throws IOException

Specified by:

collect in interface LeafCollector

Specified by:

collect in class SimpleCollector

Throws:

IOException

retrieveGroup

protected abstract SecondPassGroupingCollector.SearchGroupDocs<T> retrieveGroup(int doc)
                                                                         throws IOException

Returns the group the specified doc belongs to or null if no group could be retrieved.

Parameters:

doc - The specified doc

Returns:

the group the specified doc belongs to or null if no group could be retrieved

Throws:

IOException - If an I/O related error occurred

doSetNextReader

protected void doSetNextReader(LeafReaderContext readerContext)
                        throws IOException

Overrides:

doSetNextReader in class SimpleCollector

Throws:

IOException

getTopGroups

public TopGroups<T> getTopGroups(int withinGroupOffset)