org.apache.lucene.search.function
public class ReverseOrdFieldSource extends ValueSource
FieldCache
using getStringIndex()
and reverses the order.
The native lucene index order is used to assign an ordinal value for each field value.
Field values (terms) are lexicographically ordered by unicode value, and numbered starting at 1.
Example of reverse ordinal (rord):
If there were only three field values: "apple","banana","pear"
then rord("apple")=3, rord("banana")=2, ord("pear")=1
WARNING: rord() depends on the position in an index and can thus change when other documents are inserted or deleted, or if a MultiSearcher is used.
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.
Field Summary | |
---|---|
String | field |
Constructor Summary | |
---|---|
ReverseOrdFieldSource(String field)
Contructor for a certain field. |
Method Summary | |
---|---|
String | description() |
boolean | equals(Object o) |
DocValues | getValues(IndexReader reader) |
int | hashCode() |
Parameters: field field whose values reverse order is used.