org.apache.solr.search.function
Class ReverseOrdFieldSource
java.lang.Object
org.apache.solr.search.function.ValueSource
org.apache.solr.search.function.ReverseOrdFieldSource
- All Implemented Interfaces:
- Serializable
public class ReverseOrdFieldSource
- extends ValueSource
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: ord() 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: as of Solr 1.4, ord() and rord() can cause excess memory use since they must use a FieldCache entry
at the top level reader, while sorting and function queries now use entries at the segment level. Hence sorting
or using a different function query, in addition to ord()/rord() will double memory use.
- Version:
- $Id: ReverseOrdFieldSource.java 826531 2009-10-18 21:41:54Z yonik $
- See Also:
- Serialized Form
field
public String field
ReverseOrdFieldSource
public ReverseOrdFieldSource(String field)
description
public String description()
- Description copied from class:
ValueSource
- description of field, used in explain()
- Specified by:
description
in class ValueSource
getValues
public DocValues getValues(Map context,
IndexReader reader)
throws IOException
- Description copied from class:
ValueSource
- Gets the values for this reader and the context that was previously
passed to createWeight()
- Overrides:
getValues
in class ValueSource
- Throws:
IOException
equals
public boolean equals(Object o)
- Specified by:
equals
in class ValueSource
hashCode
public int hashCode()
- Specified by:
hashCode
in class ValueSource
Copyright © 2009 Apache Software Foundation. All Rights Reserved.