Package org.apache.lucene.search.grouping

Class DistinctValuesCollector<T,R>

java.lang.Object

org.apache.lucene.search.SimpleCollector

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

org.apache.lucene.search.grouping.DistinctValuesCollector<T,R>

All Implemented Interfaces:

Collector, LeafCollector

public class DistinctValuesCollector<T,R>
extends SecondPassGroupingCollector<T>

A second pass grouping collector that keeps track of distinct values for a specified field for the top N group.

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

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	DistinctValuesCollector.GroupCount<T,R>	Returned by getGroups(), representing the value and set of distinct values for the group.

Field Summary

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

groupReducer, groups, groupSelector, totalGroupedHitCount, totalHitCount

Constructor Summary

Constructors

Constructor	Description
DistinctValuesCollector(GroupSelector<T> groupSelector, Collection<SearchGroup<T>> groups, GroupSelector<R> valueSelector)	Create a DistinctValuesCollector

Method Summary

Modifier and Type	Method	Description
List<DistinctValuesCollector.GroupCount<T,R>>	getGroups()	Returns all unique values for each top N group.

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

collect, doSetNextReader, getGroupSelector, scoreMode, setScorer

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

Constructor Details

DistinctValuesCollector

public DistinctValuesCollector(GroupSelector<T> groupSelector,
 Collection<SearchGroup<T>> groups,
 GroupSelector<R> valueSelector)

Create a DistinctValuesCollector

Parameters:

groupSelector - the group selector to determine the top-level groups

groups - the top-level groups to collect for

valueSelector - a group selector to determine which values to collect per-group

Method Details

getGroups

public List<DistinctValuesCollector.GroupCount<T,R>> getGroups()

Returns all unique values for each top N group.

Returns:

all unique values for each top N group