org.apache.lucene.search.grouping

Class AllGroupsCollector<T>

java.lang.Object

org.apache.lucene.search.SimpleCollector

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

All Implemented Interfaces:

Collector, LeafCollector

public class AllGroupsCollector<T>
extends SimpleCollector

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.

Constructor Summary

Constructors

Constructor and Description
AllGroupsCollector(GroupSelector<T> groupSelector) Create a new AllGroupsCollector

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.
int	getGroupCount() Returns the total number of groups for the executed search.
java.util.Collection<T>	getGroups() Returns the group values
boolean	needsScores() Indicates if document scores are needed by this collector.
void	setScorer(Scorer scorer) Called before successive calls to LeafCollector.collect(int).

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

AllGroupsCollector

public AllGroupsCollector(GroupSelector<T> groupSelector)

Create a new AllGroupsCollector

Parameters:

groupSelector - the GroupSelector to determine groups

Method Detail

getGroupCount

public int getGroupCount()

Returns the total number of groups for the executed search. This is a convenience method. The following code snippet has the same effect:

getGroups().size()

Returns:

The total number of groups for the executed search

getGroups

public java.util.Collection<T> getGroups()

Returns the group values

This is an unordered collections of group values.

Returns:

the group values

setScorer

public void setScorer(Scorer scorer)
               throws java.io.IOException

Description copied from interface: LeafCollector

Called before successive calls to LeafCollector.collect(int). Implementations that need the score of the current document (passed-in to LeafCollector.collect(int)), should save the passed-in Scorer and call scorer.score() when needed.

Specified by:

setScorer in interface LeafCollector

Overrides:

setScorer in class SimpleCollector

Throws:

java.io.IOException

doSetNextReader

protected void doSetNextReader(LeafReaderContext context)
                        throws java.io.IOException

Description copied from class: SimpleCollector

This method is called before collecting context.

Overrides:

doSetNextReader in class SimpleCollector

Throws:

java.io.IOException

collect

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

java.io.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.