Package org.apache.lucene.search.function

Class CustomScoreQuery

  • All Implemented Interfaces:
    Serializable, Cloneable
    public class CustomScoreQuery
extends Query
    Query that sets document score as a programmatic function of several (sub) scores:
    1. the score of its subQuery (any query)
    2. (optional) the score of its ValueSourceQuery (or queries). For most simple/convenient use cases this query is likely to be a FieldScoreQuery
    Subclasses can modify the computation by overriding getCustomScoreProvider(org.apache.lucene.index.IndexReader).
    See Also:
    Serialized Form
    WARNING: This API is experimental and might change in incompatible ways in the next release.

    • Constructor Detail

      • CustomScoreQuery

        public CustomScoreQuery​(Query subQuery)
        Create a CustomScoreQuery over input subQuery.
        Parameters:
        subQuery - the sub query whose scored is being customized. Must not be null.

      • CustomScoreQuery

        public CustomScoreQuery​(Query subQuery,
                        ValueSourceQuery valSrcQuery)
        Create a CustomScoreQuery over input subQuery and a ValueSourceQuery.
        Parameters:
        subQuery - the sub query whose score is being customized. Must not be null.
        valSrcQuery - a value source query whose scores are used in the custom score computation. For most simple/convenient use case this would be a FieldScoreQuery. This parameter is optional - it can be null.

      • CustomScoreQuery

        public CustomScoreQuery​(Query subQuery,
                        ValueSourceQuery... valSrcQueries)
        Create a CustomScoreQuery over input subQuery and a ValueSourceQuery.
        Parameters:
        subQuery - the sub query whose score is being customized. Must not be null.
        valSrcQueries - value source queries whose scores are used in the custom score computation. For most simple/convenient use case these would be FieldScoreQueries. This parameter is optional - it can be null or even an empty array.

    • Method Detail

      • rewrite

        public Query rewrite​(IndexReader reader)
              throws IOException
        Description copied from class: Query
        Expert: called to re-write queries into primitive queries. For example, a PrefixQuery will be rewritten into a BooleanQuery that consists of TermQuerys.
        Overrides:
        rewrite in class Query
        Throws:
        IOException

      • extractTerms

        public void extractTerms​(Set<Term> terms)
        Description copied from class: Query
        Expert: adds all terms occurring in this query to the terms set. Only works if this query is in its rewritten form.
        Overrides:
        extractTerms in class Query

      • clone

        public Object clone()
        Description copied from class: Query
        Returns a clone of this query.
        Overrides:
        clone in class Query

      • toString

        public String toString​(String field)
        Description copied from class: Query
        Prints a query to a string, with field assumed to be the default field and omitted.

        The representation used is one that is supposed to be readable by QueryParser. However, there are the following limitations:

        • If the query was created by the parser, the printed representation may not be exactly what was parsed. For example, characters that need to be escaped will be represented without the required backslash.
        • Some of the more complicated queries (e.g. span queries) don't have a representation that can be parsed by QueryParser.
        Specified by:
        toString in class Query

      • equals

        public boolean equals​(Object o)
        Returns true if o is equal to this.
        Overrides:
        equals in class Query

      • hashCode

        public int hashCode()
        Returns a hash code value for this object.
        Overrides:
        hashCode in class Query

      • createWeight

        public Weight createWeight​(Searcher searcher)
                    throws IOException
        Description copied from class: Query
        Expert: Constructs an appropriate Weight implementation for this query.

        Only implemented by primitive queries, which re-write to themselves.

        Overrides:
        createWeight in class Query
        Throws:
        IOException

      • isStrict

        public boolean isStrict()
        Checks if this is strict custom scoring. In strict custom scoring, the ValueSource part does not participate in weight normalization. This may be useful when one wants full control over how scores are modified, and does not care about normalizing by the ValueSource part. One particular case where this is useful if for testing this query.

        Note: only has effect when the ValueSource part is not null.

      • setStrict

        public void setStrict​(boolean strict)
        Set the strict mode of this query.
        Parameters:
        strict - The strict mode to set.
        See Also:
        isStrict()