org.apache.lucene.search.grouping.function

Class FunctionAllGroupsCollector

java.lang.Object

org.apache.lucene.search.SimpleCollector

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

org.apache.lucene.search.grouping.function.FunctionAllGroupsCollector

All Implemented Interfaces:

Collector, LeafCollector

public class FunctionAllGroupsCollector
extends AbstractAllGroupsCollector<MutableValue>

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: Uses ValueSource and FunctionValues to retrieve the field values to group by.

Constructor Summary

Constructors

Constructor and Description
FunctionAllGroupsCollector(ValueSource groupBy, Map<?,?> vsContext) Constructs a FunctionAllGroupsCollector instance.

Method Summary

Modifier and Type	Method and Description
void	collect(int doc) Called once for every document matching a query, with the unbased document number.
protected void	doSetNextReader(LeafReaderContext context) This method is called before collecting context.
Collection<MutableValue>	getGroups() Returns the group values
boolean	needsScores() Indicates if document scores are needed by this collector.

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

FunctionAllGroupsCollector

public FunctionAllGroupsCollector(ValueSource groupBy,
                                  Map<?,?> vsContext)

Constructs a FunctionAllGroupsCollector instance.

Parameters:

groupBy - The ValueSource to group by

vsContext - The ValueSource context

Method Detail

getGroups

public Collection<MutableValue> 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<MutableValue>

Returns:

the group values

collect

public void collect(int doc)
             throws IOException

Description copied from interface: LeafCollector

Called once for every document matching a query, with the unbased document number.

Note: The collection of the current segment can be terminated by throwing a CollectionTerminatedException. In this case, the last docs of the current LeafReaderContext will be skipped and IndexSearcher will swallow the exception and continue collection with the next leaf.

Note: This is called in an inner search loop. For good search performance, implementations of this method should not call IndexSearcher.doc(int) or IndexReader.document(int) on every hit. Doing so can slow searches by an order of magnitude or more.

Specified by:

collect in interface LeafCollector

Specified by:

collect in class SimpleCollector

Throws:

IOException

doSetNextReader

protected void doSetNextReader(LeafReaderContext context)
                        throws IOException

Description copied from class: SimpleCollector

This method is called before collecting context.

Overrides:

doSetNextReader in class SimpleCollector

Throws:

IOException

needsScores

public boolean needsScores()

Description copied from interface: Collector

Indicates if document scores are needed by this collector.

Returns:

true if scores are needed.