Package org.apache.lucene.search.grouping

Class FirstPassGroupingCollectorManager<T>

java.lang.Object

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

All Implemented Interfaces:

CollectorManager<FirstPassGroupingCollector<T>,Collection<SearchGroup<T>>>

public class FirstPassGroupingCollectorManager<T>
extends Object
implements CollectorManager<FirstPassGroupingCollector<T>,Collection<SearchGroup<T>>>

A CollectorManager implementation for FirstPassGroupingCollector that supports parallel collection and merges results across segments.

Example usage:

 IndexSearcher searcher = new IndexSearcher(reader);
 Sort groupSort = Sort.RELEVANCE;
 int topNGroups = 10;

 FirstPassGroupingCollectorManager<BytesRef> manager =
     new FirstPassGroupingCollectorManager<>(
         () -> new TermGroupSelector("category"),
         groupSort,
         0,
         topNGroups);

 Collection<SearchGroup<BytesRef>> searchGroups = searcher.search(query, manager);

 // searchGroups can then be passed to a second pass collector manager like TopGroupsCollectorManager for full group results
 

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

Constructor Summary

Constructors

Constructor	Description
FirstPassGroupingCollectorManager(Supplier<GroupSelector<T>> groupSelectorFactory, Sort groupSort, int groupOffset, int topNGroups)	Creates a new FirstPassGroupingCollectorManager.
FirstPassGroupingCollectorManager(Supplier<GroupSelector<T>> groupSelectorFactory, Sort groupSort, int groupOffset, int topNGroups, boolean ignoreDocsWithoutGroupField)	Creates a new FirstPassGroupingCollectorManager.

Method Summary

Modifier and Type	Method	Description
FirstPassGroupingCollector<T>	newCollector()
Collection<SearchGroup<T>>	reduce(Collection<FirstPassGroupingCollector<T>> collectors)

Methods inherited from class java.lang.Object

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

Constructor Details

FirstPassGroupingCollectorManager

public FirstPassGroupingCollectorManager(Supplier<GroupSelector<T>> groupSelectorFactory,
 Sort groupSort,
 int groupOffset,
 int topNGroups)

Creates a new FirstPassGroupingCollectorManager.

Parameters:

groupSelectorFactory - factory to create group selectors for each collector

groupSort - the sort to use for groups

groupOffset - The offset in the collected groups

topNGroups - the number of top groups to collect

FirstPassGroupingCollectorManager

public FirstPassGroupingCollectorManager(Supplier<GroupSelector<T>> groupSelectorFactory,
 Sort groupSort,
 int groupOffset,
 int topNGroups,
 boolean ignoreDocsWithoutGroupField)

Creates a new FirstPassGroupingCollectorManager.

Parameters:

groupSelectorFactory - factory to create group selectors for each collector

groupSort - the sort to use for groups

groupOffset - The offset in the collected groups

topNGroups - the number of top groups to collect

ignoreDocsWithoutGroupField - whether to ignore documents without a group field

Method Details

newCollector

public FirstPassGroupingCollector<T> newCollector()
                                           throws IOException

Specified by:

newCollector in interface CollectorManager<FirstPassGroupingCollector<T>,Collection<SearchGroup<T>>>

Throws:

IOException

reduce

public Collection<SearchGroup<T>> reduce(Collection<FirstPassGroupingCollector<T>> collectors)
                                  throws IOException

Specified by:

reduce in interface CollectorManager<FirstPassGroupingCollector<T>,Collection<SearchGroup<T>>>

Throws:

IOException