Package org.apache.solr.ltr.feature

Class FieldLengthFeature

java.lang.Object

org.apache.lucene.search.Query

org.apache.solr.ltr.feature.Feature

org.apache.solr.ltr.feature.FieldLengthFeature

All Implemented Interfaces:

org.apache.lucene.util.Accountable

public class FieldLengthFeature
extends Feature

This feature returns the length of a field (in terms) for the current document. Example configuration:

 {
   "name":  "titleLength",
   "class": "org.apache.solr.ltr.feature.FieldLengthFeature",
   "params": {
     "field": "title"
   }
 }
 

Note: since this feature relies on norms values that are stored in a single byte the value of the feature could have a lightly different value. (see also ClassicSimilarity)

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
class	FieldLengthFeature.FieldLengthFeatureWeight

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

Fields inherited from interface org.apache.lucene.util.Accountable

NULL_ACCOUNTABLE

Constructor Summary

Constructors

Constructor	Description
FieldLengthFeature(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)
String	getField()
LinkedHashMap<String,Object>	paramsToMap()
void	setField(String field)
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

defaultParamsToMap, equals, getDefaultValue, getIndex, getInstance, getName, hashCode, ramBytesUsed, setDefaultValue, setIndex, toString, visit

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

Methods inherited from interface org.apache.lucene.util.Accountable

getChildResources

Constructor Detail

FieldLengthFeature

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

Method Detail

getField

public String getField()

setField

public void setField(String field)

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