org.apache.solr.search
Class CollapsingQParserPlugin

java.lang.Object
  org.apache.solr.search.QParserPlugin
      org.apache.solr.search.CollapsingQParserPlugin

All Implemented Interfaces:

SolrInfoMBean, NamedListInitializedPlugin

public class CollapsingQParserPlugin
extends QParserPlugin

The CollapsingQParserPlugin is a PostFilter that performs field collapsing. This is a high performance alternative to standard Solr field collapsing (with ngroups) when the number of distinct groups in the result set is high.

Sample syntax:

Collapse based on the highest scoring document:

fq=(!collapse field=field_name}

Collapse based on the min value of a numeric field:

fq={!collapse field=field_name min=field_name}

Collapse based on the max value of a numeric field:

fq={!collapse field=field_name max=field_name}

Collapse with a null policy:

fq={!collapse field=field_name nullPolicy=nullPolicy}

There are three null policies:
ignore : removes docs with a null value in the collapse field (default).
expand : treats each doc with a null value in the collapse field as a separate group.
collapse : collapses all docs with a null value into a single group using either highest score, or min/max.

The CollapsingQParserPlugin fully supports the QueryElevationComponent

Nested Class Summary

static class	CollapsingQParserPlugin.CollapseScore
class	CollapsingQParserPlugin.CollapsingPostFilter

Nested classes/interfaces inherited from interface org.apache.solr.core.SolrInfoMBean

SolrInfoMBean.Category

Field Summary

static String	NAME
static String	NULL_COLLAPSE
static String	NULL_EXPAND
static String	NULL_IGNORE

Fields inherited from class org.apache.solr.search.QParserPlugin

DEFAULT_QTYPE, standardPlugins

Constructor Summary

CollapsingQParserPlugin()

Method Summary

QParser	createParser(String qstr, SolrParams localParams, SolrParams params, SolrQueryRequest request) return a QParser
void	init(NamedList namedList)

Methods inherited from class org.apache.solr.search.QParserPlugin

getCategory, getDescription, getDocs, getName, getSource, getStatistics, getVersion

Methods inherited from class java.lang.Object

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

Field Detail

NAME

public static final String NAME

See Also:

Constant Field Values

NULL_COLLAPSE

public static final String NULL_COLLAPSE

See Also:

Constant Field Values

NULL_IGNORE

public static final String NULL_IGNORE

See Also:

Constant Field Values

NULL_EXPAND

public static final String NULL_EXPAND

See Also:

Constant Field Values

Constructor Detail

CollapsingQParserPlugin

public CollapsingQParserPlugin()

Method Detail

init

public void init(NamedList namedList)

createParser

public QParser createParser(String qstr,
                            SolrParams localParams,
                            SolrParams params,
                            SolrQueryRequest request)

Description copied from class: QParserPlugin

return a QParser

Specified by:

createParser in class QParserPlugin