Package org.apache.solr.ltr.feature

Class ValueFeature

java.lang.Object

org.apache.lucene.search.Query

org.apache.solr.ltr.feature.Feature

org.apache.solr.ltr.feature.ValueFeature

public class ValueFeature
extends Feature

This feature allows to return a constant given value for the current document. Example configuration:

{
   "name" : "userFromMobile",
   "class" : "org.apache.solr.ltr.feature.ValueFeature",
   "params" : { "value" : "${userFromMobile}", "required":true }
 }

You can place a constant value like "1.3f" in the value params, but many times you would want to pass in external information to use per request. For instance, maybe you want to rank things differently if the search came from a mobile device, or maybe you want to use your external query intent system as a feature. In the rerank request you can pass in rq={... efi.userFromMobile=1}, and the above feature will return 1 for all the docs for that request. If required is set to true, the request will return an error since you failed to pass in the efi, otherwise if will just skip the feature and use a default value of 0 instead.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
class	ValueFeature.ValueFeatureWeight

Nested classes/interfaces inherited from class org.apache.solr.ltr.feature.Feature

Feature.FeatureWeight

Field Summary

Fields inherited from class org.apache.solr.ltr.feature.Feature

name

Constructor Summary

Constructors

Constructor	Description
ValueFeature(String name, Map<String,Object> params)

Method Summary

Modifier and Type	Method	Description
Feature.FeatureWeight	createWeight(org.apache.lucene.search.IndexSearcher searcher, boolean needsScores, SolrQueryRequest request, org.apache.lucene.search.Query originalQuery, Map<String,String[]> efi)
Object	getValue()
boolean	isRequired()
LinkedHashMap<String,Object>	paramsToMap()
void	setRequired(boolean required)
void	setValue(Object value)
protected void	validate()	As part of creation of a feature instance, this function confirms that the feature parameters are valid.

Methods inherited from class org.apache.solr.ltr.feature.Feature

equals, getDefaultValue, getIndex, getInstance, getName, hashCode, setDefaultValue, setIndex, toString

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

classHash, createWeight, rewrite, sameClassAs, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

ValueFeature

public ValueFeature(String name,
                    Map<String,Object> params)

Method Detail

getValue

public Object getValue()

setValue

public void setValue(Object value)

isRequired

public boolean isRequired()

setRequired

public void setRequired(boolean required)

paramsToMap

public LinkedHashMap<String,Object> paramsToMap()

Specified by:

paramsToMap in class Feature

validate

protected void validate()
                 throws FeatureException

Description copied from class: Feature

As part of creation of a feature instance, this function confirms that the feature parameters are valid.

Specified by:

validate in class Feature

Throws:

FeatureException - Feature Exception

createWeight

public Feature.FeatureWeight createWeight(org.apache.lucene.search.IndexSearcher searcher,
                                          boolean needsScores,
                                          SolrQueryRequest request,
                                          org.apache.lucene.search.Query originalQuery,
                                          Map<String,String[]> efi)
                                   throws IOException

Specified by:

createWeight in class Feature

Throws:

IOException