Module org.apache.lucene.grouping

Package 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:

DistinctValuesCollector, TopGroupsCollector

public class SecondPassGroupingCollector<T>
extends SimpleCollector

SecondPassGroupingCollector runs over an already collected set of groups, further applying a GroupReducer to each group

See Also:

• TopGroupsCollector
• DistinctValuesCollector

Field Summary

Fields

Modifier and Type	Field	Description
protected final GroupReducer<T,?>	groupReducer
protected final Collection<SearchGroup<T>>	groups
protected final GroupSelector<T>	groupSelector
protected int	totalGroupedHitCount
protected int	totalHitCount

Constructor Summary

Constructors

Constructor	Description
SecondPassGroupingCollector(GroupSelector<T> groupSelector, Collection<SearchGroup<T>> groups, GroupReducer<T,?> reducer)	Create a new SecondPassGroupingCollector

Method Summary

Modifier and Type	Method	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.
GroupSelector<T>	getGroupSelector()
ScoreMode	scoreMode()	Indicates what features are required from the scorer.
void	setScorer(Scorable 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

setWeight

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

collect, competitiveIterator, finish

Field Details

groupSelector

protected final GroupSelector<T> groupSelector

groups

protected final Collection<SearchGroup<T>> groups

groupReducer

protected final GroupReducer<T,?> groupReducer

totalHitCount

protected int totalHitCount

totalGroupedHitCount

protected int totalGroupedHitCount

Constructor Details

SecondPassGroupingCollector

public SecondPassGroupingCollector(GroupSelector<T> groupSelector,
 Collection<SearchGroup<T>> groups,
 GroupReducer<T,?> reducer)

Create a new SecondPassGroupingCollector

Parameters:

groupSelector - the GroupSelector that defines groups for this search

groups - the groups to collect documents for

reducer - the reducer to apply to each group

Method Details

getGroupSelector

public GroupSelector<T> getGroupSelector()

Returns:

the GroupSelector used in this collector

scoreMode

public ScoreMode scoreMode()

Description copied from interface: Collector

Indicates what features are required from the scorer.

setScorer

public void setScorer(Scorable 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 StoredFields.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

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