org.apache.solr.search

Class SwitchQParserPlugin

java.lang.Object

org.apache.solr.search.QParserPlugin

org.apache.solr.search.SwitchQParserPlugin

All Implemented Interfaces:

NamedListInitializedPlugin

public class SwitchQParserPlugin
extends QParserPlugin

A QParserPlugin that acts like a "switch/case" statement.

QParser's produced by this plugin will take their primary input string, trimmed and prefixed with "case.", to use as a key to lookup a "switch case" in the parser's local params. If a matching local param is found the resulting param value will then be parsed as a subquery, and returned as the parse result.

The "case" local param can be optionally be specified as a switch case to match missing (or blank) input strings. The "default" local param can optionally be specified as a default case to use if the input string does not match any other switch case local params. If default is not specified, then any input which does not match a switch case local param will result in a syntax error.

In the examples below, the result of each query would be XXX....

  q={!switch case.foo=XXX case.bar=zzz case.yak=qqq}foo
  q={!switch case.foo=qqq case.bar=XXX case.yak=zzz} bar  // extra whitespace
  q={!switch case.foo=qqq case.bar=zzz default=XXX}asdf   // fallback on default
  q={!switch case=XXX case.bar=zzz case.yak=qqq}          // blank input
 

A practical usage of this QParsePlugin, is in specifying "appends" fq params in the configuration of a SearchHandler, to provide a fixed set of filter options for clients using custom parameter names. Using the example configuration below, clients can optionally specify the custom parameters in_stock and shipping to override the default filtering behavior, but are limited to the specific set of legal values (shipping=any|free, in_stock=yes|no|all).

 <requestHandler name="/select" class="solr.SearchHandler">
   <lst name="defaults">
     <str name="in_stock">yes</str>
     <str name="shipping">any</str>
   </lst>
   <lst name="appends">
     <str name="fq">{!switch case.all='*:*'
                             case.yes='inStock:true'
                             case.no='inStock:false'
                             v=$in_stock}</str>
     <str name="fq">{!switch case.any='*:*'
                             case.free='shipping_cost:0.0'
                             v=$shipping}</str>
   </lst>
 </requestHandler>

Field Summary

Fields

Modifier and Type	Field and Description
static String	NAME
static String	SWITCH_CASE Used as both a local params key to find the "default" if no blank input is provided to the parser, as well as a prefix (followed by '.' for looking up the switch input.
static String	SWITCH_DEFAULT A local param whose value, if specified, is used if no switch case matches the parser input.

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

DEFAULT_QTYPE, standardPlugins

Constructor Summary

Constructors

Constructor and Description
SwitchQParserPlugin()

Method Summary

Methods

Modifier and Type	Method and Description
QParser	createParser(String qstr, SolrParams localParams, SolrParams params, SolrQueryRequest req) return a QParser
void	init(NamedList args)

Methods inherited from class java.lang.Object

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

Field Detail

NAME

public static String NAME

SWITCH_CASE

public static String SWITCH_CASE

Used as both a local params key to find the "default" if no blank input is provided to the parser, as well as a prefix (followed by '.' for looking up the switch input.

SWITCH_DEFAULT

public static String SWITCH_DEFAULT

A local param whose value, if specified, is used if no switch case matches the parser input. If this param is not specified, and no switch case matches the parser input, an error is returned.

Constructor Detail

SwitchQParserPlugin

public SwitchQParserPlugin()

Method Detail

init

public void init(NamedList args)

createParser

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

Description copied from class: QParserPlugin

return a QParser

Specified by:

createParser in class QParserPlugin