org.apache.lucene.search.grouping

Class AbstractSecondPassGroupingCollector<GROUP_VALUE_TYPE>

java.lang.Object

org.apache.lucene.search.SimpleCollector

org.apache.lucene.search.grouping.AbstractSecondPassGroupingCollector<GROUP_VALUE_TYPE>

All Implemented Interfaces:

Collector, LeafCollector

Direct Known Subclasses:

FunctionSecondPassGroupingCollector, TermSecondPassGroupingCollector

public abstract class AbstractSecondPassGroupingCollector<GROUP_VALUE_TYPE>
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.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	AbstractSecondPassGroupingCollector.SearchGroupDocs<GROUP_VALUE_TYPE>

Field Summary

Fields

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

Constructor Summary

Constructors

Constructor and Description
AbstractSecondPassGroupingCollector(Collection<SearchGroup<GROUP_VALUE_TYPE>> 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) Called once for every document matching a query, with the unbased document number.
protected void	doSetNextReader(LeafReaderContext readerContext) This method is called before collecting context.
TopGroups<GROUP_VALUE_TYPE>	getTopGroups(int withinGroupOffset)
protected abstract AbstractSecondPassGroupingCollector.SearchGroupDocs<GROUP_VALUE_TYPE>	retrieveGroup(int doc) Returns the group the specified doc belongs to or null if no group could be retrieved.
void	setScorer(Scorer scorer) Called before successive calls to LeafCollector.collect(int).

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

Methods inherited from interface org.apache.lucene.search.Collector

needsScores

Field Detail

groupMap

protected final Map<GROUP_VALUE_TYPE,AbstractSecondPassGroupingCollector.SearchGroupDocs<GROUP_VALUE_TYPE>> groupMap

groupDocs

protected AbstractSecondPassGroupingCollector.SearchGroupDocs<GROUP_VALUE_TYPE>[] groupDocs

Constructor Detail

AbstractSecondPassGroupingCollector

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

Throws:

IOException

Method Detail

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

collect

public void collect(int doc)
             throws IOException

Description copied from interface: LeafCollector

Called once for every document matching a query, with the unbased document number.

Note: The collection of the current segment can be terminated by throwing a CollectionTerminatedException. In this case, the last docs of the current LeafReaderContext will be skipped and IndexSearcher will swallow the exception and continue collection with the next leaf.

Note: This is called in an inner search loop. For good search performance, implementations of this method should not call IndexSearcher.doc(int) or IndexReader.document(int) on every hit. Doing so can slow searches by an order of magnitude or more.

Specified by:

collect in interface LeafCollector

Specified by:

collect in class SimpleCollector

Throws:

IOException

retrieveGroup

protected abstract AbstractSecondPassGroupingCollector.SearchGroupDocs<GROUP_VALUE_TYPE> 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

Description copied from class: SimpleCollector

This method is called before collecting context.

Overrides:

doSetNextReader in class SimpleCollector

Throws:

IOException

getTopGroups

public TopGroups<GROUP_VALUE_TYPE> getTopGroups(int withinGroupOffset)