org.apache.lucene.search.function
public abstract class ValueSource extends Object implements Serializable
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.
Method Summary | |
---|---|
abstract String | description()
description of field, used in explain() |
abstract boolean | equals(Object o)
Needed for possible caching of query results - used by equals. |
abstract DocValues | getValues(IndexReader reader)
Return the DocValues used by the function query. |
abstract int | hashCode()
Needed for possible caching of query results - used by hashCode. |
String | toString() |
See Also: Object#equals(Object)
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.
See Also: Object#hashCode()