org.apache.lucene.search.grouping.term

Class TermAllGroupsCollector

java.lang.Object

org.apache.lucene.search.SimpleCollector

org.apache.lucene.search.grouping.AbstractAllGroupsCollector<BytesRef>

org.apache.lucene.search.grouping.term.TermAllGroupsCollector

All Implemented Interfaces:

Collector, LeafCollector

public class TermAllGroupsCollector
extends AbstractAllGroupsCollector<BytesRef>

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(String groupField) Constructs a AbstractAllGroupsCollector.
TermAllGroupsCollector(String groupField, int initialSize) Expert: Constructs a AbstractAllGroupsCollector

Method Summary

Methods

Modifier and Type	Method and Description
void	collect(int doc)
protected void	doSetNextReader(LeafReaderContext context)
Collection<BytesRef>	getGroups() Returns the group values
boolean	needsScores()

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

getGroupCount, 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

Constructor Detail

TermAllGroupsCollector

public TermAllGroupsCollector(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(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 IOException

Specified by:

collect in interface LeafCollector

Specified by:

collect in class SimpleCollector

Throws:

IOException

getGroups

public Collection<BytesRef> getGroups()

Description copied from class: AbstractAllGroupsCollector

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<BytesRef>

Returns:

the group values

doSetNextReader

protected void doSetNextReader(LeafReaderContext context)
                        throws IOException

Overrides:

doSetNextReader in class SimpleCollector

Throws:

IOException

needsScores

public boolean needsScores()