org.apache.lucene.search.function

Class ReverseOrdFieldSource

public class ReverseOrdFieldSource extends ValueSource

Expert: obtains the ordinal of the field value from the default Lucene 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.

Author: yonik

Field Summary
Stringfield
Constructor Summary
ReverseOrdFieldSource(String field)
Contructor for a certain field.
Method Summary
Stringdescription()
booleanequals(Object o)
DocValuesgetValues(IndexReader reader)
inthashCode()

Field Detail

field

public String field

Constructor Detail

ReverseOrdFieldSource

public ReverseOrdFieldSource(String field)
Contructor for a certain field.

Parameters: field field whose values reverse order is used.

Method Detail

description

public String description()

equals

public boolean equals(Object o)

getValues

public DocValues getValues(IndexReader reader)

hashCode

public int hashCode()
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