org.apache.lucene.search.function

Class ValueSource

public abstract class ValueSource extends Object implements Serializable

Expert: source of values for basic function queries.

At its default/simplest form, values - one per doc - are used as the score of that doc.

Values are instantiated as DocValues for a particular reader.

ValueSource implementations differ in RAM requirements: it would always be a factor of the number of documents, but for each document the number of bytes can be 1, 2, 4, or 8.

WARNING: The status of the search.function package is experimental. The APIs introduced here might change in the future and will not be supported anymore in such a case.

Author: yonik

Method Summary
abstract Stringdescription()
description of field, used in explain()
abstract booleanequals(Object o)
Needed for possible caching of query results - used by equals.
abstract DocValuesgetValues(IndexReader reader)
Return the DocValues used by the function query.
abstract inthashCode()
Needed for possible caching of query results - used by hashCode.
StringtoString()

Method Detail

description

public abstract String description()
description of field, used in explain()

equals

public abstract boolean equals(Object o)
Needed for possible caching of query results - used by equals.

See Also: Object#equals(Object)

getValues

public abstract DocValues getValues(IndexReader reader)
Return the DocValues used by the function query.

Parameters: reader the IndexReader used to read these values. If any caching is involved, that caching would also be IndexReader based.

Throws: IOException for any error.

hashCode

public abstract int hashCode()
Needed for possible caching of query results - used by hashCode.

See Also: Object#hashCode()

toString

public String toString()
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