org.apache.lucene.search.grouping.term

Class TermDistinctValuesCollector

java.lang.Object

org.apache.lucene.search.SimpleCollector

org.apache.lucene.search.grouping.AbstractDistinctValuesCollector<TermDistinctValuesCollector.GroupCount>

org.apache.lucene.search.grouping.term.TermDistinctValuesCollector

All Implemented Interfaces:

Collector, LeafCollector

public class TermDistinctValuesCollector
extends AbstractDistinctValuesCollector<TermDistinctValuesCollector.GroupCount>

A term based implementation of AbstractDistinctValuesCollector that relies on SortedDocValues to count the distinct values per group.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	TermDistinctValuesCollector.GroupCount Holds distinct values for a single group.

Constructor Summary

Constructors

Constructor and Description
TermDistinctValuesCollector(String groupField, String countField, Collection<SearchGroup<BytesRef>> groups) Constructs TermDistinctValuesCollector instance.

Method Summary

Methods

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.
List<TermDistinctValuesCollector.GroupCount>	getGroups() Returns all unique values for each top N group.
boolean	needsScores() Indicates if document scores are needed by this collector.

Methods inherited from class org.apache.lucene.search.SimpleCollector

getLeafCollector, setScorer

Methods inherited from class java.lang.Object

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

Constructor Detail

TermDistinctValuesCollector

public TermDistinctValuesCollector(String groupField,
                           String countField,
                           Collection<SearchGroup<BytesRef>> groups)

Constructs TermDistinctValuesCollector instance.

Parameters:

groupField - The field to group by

countField - The field to count distinct values for

groups - The top N groups, collected during the first phase search

Method Detail

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

getGroups

public List<TermDistinctValuesCollector.GroupCount> getGroups()

Description copied from class: AbstractDistinctValuesCollector

Returns all unique values for each top N group.

Specified by:

getGroups in class AbstractDistinctValuesCollector<TermDistinctValuesCollector.GroupCount>

Returns:

all unique values for each top N group

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.