Class ReverseOrdFieldSource

Obtains the ordinal of the field value from the default Lucene Lucene.Net.Search.FieldCache using GetTermsIndex(AtomicReader, String, Single) 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
System.Object
ValueSource
ReverseOrdFieldSource
Inherited Members
System.Object.Equals(System.Object, System.Object)
System.Object.GetType()
System.Object.MemberwiseClone()
System.Object.ReferenceEquals(System.Object, System.Object)
Namespace: Lucene.Net.Queries.Function.ValueSources
Assembly: Lucene.Net.Queries.dll
Syntax
public class ReverseOrdFieldSource : ValueSource

Constructors

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ReverseOrdFieldSource(String)

Declaration
public ReverseOrdFieldSource(string field)
Parameters
Type Name Description
System.String field

Properties

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Field

Declaration
public string Field { get; }
Property Value
Type Description
System.String

Methods

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Equals(Object)

Declaration
public override bool Equals(object o)
Parameters
Type Name Description
System.Object o
Returns
Type Description
System.Boolean
Overrides
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GetDescription()

Declaration
public override string GetDescription()
Returns
Type Description
System.String
Overrides
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GetHashCode()

Declaration
public override int GetHashCode()
Returns
Type Description
System.Int32
Overrides
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GetValues(IDictionary, AtomicReaderContext)

Declaration
public override FunctionValues GetValues(IDictionary context, AtomicReaderContext readerContext)
Parameters
Type Name Description
System.Collections.IDictionary context
Lucene.Net.Index.AtomicReaderContext readerContext
Returns
Type Description
FunctionValues
Overrides