Class ICUFoldingFilter

A TokenFilter that applies search term folding to Unicode text, applying foldings from UTR#30 Character Foldings.

Inheritance
System.Object
AttributeSource
TokenStream
TokenFilter
ICUNormalizer2Filter
ICUFoldingFilter
Implements
System.IDisposable
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.Analysis.Icu
Assembly: Lucene.Net.ICU.dll
Syntax
public sealed class ICUFoldingFilter : ICUNormalizer2Filter, IDisposable
Remarks

This filter applies the following foldings from the report to unicode text:

  • Accent removal
  • Case folding
  • Canonical duplicates folding
  • Dashes folding
  • Diacritic removal (including stroke, hook, descender)
  • Greek letterforms folding
  • Han Radical folding
  • Hebrew Alternates folding
  • Jamo folding
  • Letterforms folding
  • Math symbol folding
  • Multigraph Expansions: All
  • Native digit folding
  • No-break folding
  • Overline folding
  • Positional forms folding
  • Small forms folding
  • Space folding
  • Spacing Accents folding
  • Subscript folding
  • Superscript folding
  • Suzhou Numeral folding
  • Symbol folding
  • Underline folding
  • Vertical forms folding
  • Width folding

Additionally, Default Ignorables are removed, and text is normalized to NFKC. All foldings, case folding, and normalization mappings are applied recursively to ensure a fully folded and normalized result.

Constructors

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ICUFoldingFilter(TokenStream)

Create a new ICUFoldingFilter on the specified input

Declaration
public ICUFoldingFilter(TokenStream input)
Parameters
Type Name Description
TokenStream input

Implements

System.IDisposable