Package org.apache.solr.search.similarities

Class SchemaSimilarityFactory

  • All Implemented Interfaces:
    SolrCoreAware
    public class SchemaSimilarityFactory
extends SimilarityFactory
implements SolrCoreAware
    SimilarityFactory that returns a global PerFieldSimilarityWrapper that delegates to the field type, if it's configured. For field types that do not have a Similarity explicitly configured, the global Similarity will use per fieldtype defaults -- either based on an explicitly configured defaultSimFromFieldType a sensible default:
    • luceneMatchVersion >= 8.0 = BM25Similarity

    The defaultSimFromFieldType option accepts the name of any fieldtype, and uses whatever Similarity is explicitly configured for that fieldType as the default for all other field types. For example: 

       <similarity class="solr.SchemaSimilarityFactory" >
     <str name="defaultSimFromFieldType">type-using-custom-dfr</str>
   </similarity>
   ...
   <fieldType name="type-using-custom-dfr" class="solr.TextField">
     ...
     <similarity class="solr.DFRSimilarityFactory">
       <str name="basicModel">I(F)</str>
       <str name="afterEffect">B</str>
       <str name="normalization">H3</str>
       <float name="mu">900</float>
     </similarity>
   </fieldType>

    In the example above, any fieldtypes that do not define their own </similarity/> will use the Similarity configured for the type-using-custom-dfr .

    NOTE: Users should be aware that even when this factory uses a single default Similarity for some or all fields in a Query, the behavior can be inconsistent with the behavior of explicitly configuring that same Similarity globally, because of differences in how some multi-field / multi-clause behavior is defined in PerFieldSimilarityWrapper.

    See Also:
    FieldType.getSimilarity()

    • Constructor Detail

      • SchemaSimilarityFactory

        public SchemaSimilarityFactory()