org.apache.lucene.search.grouping

Class Grouper<T>

java.lang.Object

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

Type Parameters:

T - the type the group value

Direct Known Subclasses:

FunctionGrouper, TermGrouper

public abstract class Grouper<T>
extends Object

A factory object to create first and second-pass collectors, run by a GroupingSearch

Constructor Summary

Constructors

Constructor and Description
Grouper()

Method Summary

Modifier and Type	Method and Description
abstract AllGroupsCollector<T>	getAllGroupsCollector() Create an AllGroupsCollector
abstract FirstPassGroupingCollector<T>	getFirstPassCollector(Sort sort, int count) Create a first-pass collector
abstract AllGroupHeadsCollector<T>	getGroupHeadsCollector(Sort sort) Create an AllGroupHeadsCollector
abstract SecondPassGroupingCollector<T>	getSecondPassCollector(Collection<SearchGroup<T>> groups, Sort groupSort, Sort withinGroupSort, int maxDocsPerGroup, boolean getScores, boolean getMaxScores, boolean fillSortFields) Create a second-pass collector

Methods inherited from class java.lang.Object

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

Constructor Detail

Grouper

public Grouper()

Method Detail

getFirstPassCollector

public abstract FirstPassGroupingCollector<T> getFirstPassCollector(Sort sort,
                                                                    int count)
                                                             throws IOException

Create a first-pass collector

Parameters:

sort - the order in which groups should be returned

count - how many groups to return

Throws:

IOException

getAllGroupsCollector

public abstract AllGroupsCollector<T> getAllGroupsCollector()

Create an AllGroupsCollector

getGroupHeadsCollector

public abstract AllGroupHeadsCollector<T> getGroupHeadsCollector(Sort sort)

Create an AllGroupHeadsCollector

Parameters:

sort - a within-group sort order to determine which doc is the group head

getSecondPassCollector

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

Create a second-pass collector

Throws:

IOException