Class ReverseOrdFieldSource

Obtains the ordinal of the field value from the default Lucene Lucene.Net.Search.FieldCache using GetTermsIndex(AtomicReader, string, float) 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.
Inheritance
object
ValueSource
ReverseOrdFieldSource
Inherited Members
Namespace: Lucene.Net.Queries.Function.ValueSources
Assembly: Lucene.Net.Queries.dll
Syntax
public class ReverseOrdFieldSource : ValueSource

Constructors

ReverseOrdFieldSource(string)

Obtains the ordinal of the field value from the default Lucene Lucene.Net.Search.FieldCache using GetTermsIndex(AtomicReader, string, float) 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.
Declaration
public ReverseOrdFieldSource(string field)
Parameters
Type Name Description
string field

Properties

Field

Obtains the ordinal of the field value from the default Lucene Lucene.Net.Search.FieldCache using GetTermsIndex(AtomicReader, string, float) 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.
Declaration
public string Field { get; }
Property Value
Type Description
string

Methods

Equals(object)

Determines whether the specified object is equal to the current object.

Declaration
public override bool Equals(object o)
Parameters
Type Name Description
object o
Returns
Type Description
bool

true if the specified object is equal to the current object; otherwise, false.
Overrides

GetDescription()

description of field, used in Explain()

Declaration
public override string GetDescription()
Returns
Type Description
string
Overrides

GetHashCode()

Serves as the default hash function.

Declaration
public override int GetHashCode()
Returns
Type Description
int

A hash code for the current object.
Overrides

GetValues(IDictionary, AtomicReaderContext)

Gets the values for this reader and the context that was previously passed to CreateWeight(IDictionary, IndexSearcher)

Declaration
public override FunctionValues GetValues(IDictionary context, AtomicReaderContext readerContext)
Parameters
Type Name Description
IDictionary context
AtomicReaderContext readerContext
Returns
Type Description
FunctionValues
Overrides