org.apache.lucene.search.grouping

Class TermAllGroupsCollector

java.lang.Object

org.apache.lucene.search.Collector

org.apache.lucene.search.grouping.AbstractAllGroupsCollector<java.lang.String>

org.apache.lucene.search.grouping.TermAllGroupsCollector

public class TermAllGroupsCollector
extends AbstractAllGroupsCollector<java.lang.String>

A collector that collects all groups that match the query. Only the group value is collected, and the order is undefined. This collector does not determine the most relevant document of a group.

Implementation detail: an int hash set (SentinelIntSet) is used to detect if a group is already added to the total count. For each segment the int set is cleared and filled with previous counted groups that occur in the new segment.

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

Constructor Summary

Constructors

Constructor and Description
TermAllGroupsCollector(java.lang.String groupField) Constructs a AbstractAllGroupsCollector.
TermAllGroupsCollector(java.lang.String groupField, int initialSize) Expert: Constructs a AbstractAllGroupsCollector

Method Summary

Modifier and Type	Method and Description
void	collect(int doc)
java.util.Collection<java.lang.String>	getGroups() Returns the group values This is an unordered collections of group values.
void	setNextReader(org.apache.lucene.index.IndexReader reader, int docBase)

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

acceptsDocsOutOfOrder, getGroupCount, setScorer

Methods inherited from class java.lang.Object

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

Constructor Detail

TermAllGroupsCollector

public TermAllGroupsCollector(java.lang.String groupField,
                              int initialSize)

Expert: Constructs a AbstractAllGroupsCollector

Parameters:

groupField - The field to group by

initialSize - The initial allocation size of the internal int set and group list which should roughly match the total number of expected unique groups. Be aware that the heap usage is 4 bytes * initialSize.

TermAllGroupsCollector

public TermAllGroupsCollector(java.lang.String groupField)

Constructs a AbstractAllGroupsCollector. This sets the initial allocation size for the internal int set and group list to 128.

Parameters:

groupField - The field to group by

Method Detail

collect

public void collect(int doc)
             throws java.io.IOException

Specified by:

collect in class org.apache.lucene.search.Collector

Throws:

java.io.IOException

getGroups

public java.util.Collection<java.lang.String> getGroups()

Returns the group values

This is an unordered collections of group values. For each group that matched the query there is a BytesRef representing a group value.

Specified by:

getGroups in class AbstractAllGroupsCollector<java.lang.String>

Returns:

the group values

setNextReader

public void setNextReader(org.apache.lucene.index.IndexReader reader,
                          int docBase)
                   throws java.io.IOException

Specified by:

setNextReader in class org.apache.lucene.search.Collector

Throws:

java.io.IOException