Class ICUNormalizer2Filter
Normalize token text with ICU's ICU4N.Text.Normalizer2.
Implements
Inherited Members
TokenFilter.m_input
TokenFilter.End()
TokenFilter.Reset()
TokenStream.Dispose()
AttributeSource.GetAttributeFactory()
AttributeSource.GetAttributeClassesEnumerator()
AttributeSource.GetAttributeImplsEnumerator()
AttributeSource.AddAttributeImpl(Attribute)
AttributeSource.AddAttribute<T>()
AttributeSource.HasAttributes
AttributeSource.HasAttribute<T>()
AttributeSource.GetAttribute<T>()
AttributeSource.ClearAttributes()
AttributeSource.CaptureState()
AttributeSource.RestoreState(AttributeSource.State)
AttributeSource.GetHashCode()
AttributeSource.ReflectWith(IAttributeReflector)
AttributeSource.CloneAttributes()
AttributeSource.CopyTo(AttributeSource)
AttributeSource.ToString()
Namespace: Lucene.Net.Analysis.Icu
Assembly: Lucene.Net.ICU.dll
Syntax
public class ICUNormalizer2Filter : TokenFilter, IDisposableRemarks
With this filter, you can normalize text in the following ways:
- NFKC Normalization, Case Folding, and removing Ignorables (the default)
- Using a standard Normalization mode (NFC, NFD, NFKC, NFKD)
- Based on rules from a custom normalization mapping.
- The case folding that it does can be seen as a replacement for LowerCaseFilter: For example, it handles cases such as the Greek sigma, so that "Μάϊος" and "ΜΆΪΟΣ" will match correctly.
- The normalization will standardizes different forms of the same character in Unicode. For example, CJK full-width numbers will be standardized to their ASCII forms.
- Ignorables such as Zero-Width Joiner and Variation Selectors are removed. These are typically modifier characters that affect display.
Constructors
ICUNormalizer2Filter(TokenStream)
Create a new ICUNormalizer2Filter that combines NFKC normalization, Case Folding, and removes Default Ignorables (NFKC_Casefold)
Declaration
public ICUNormalizer2Filter(TokenStream input)Parameters
| Type | Name | Description |
|---|---|---|
| TokenStream | input |
Remarks
With this filter, you can normalize text in the following ways:
- NFKC Normalization, Case Folding, and removing Ignorables (the default)
- Using a standard Normalization mode (NFC, NFD, NFKC, NFKD)
- Based on rules from a custom normalization mapping.
- The case folding that it does can be seen as a replacement for LowerCaseFilter: For example, it handles cases such as the Greek sigma, so that "Μάϊος" and "ΜΆΪΟΣ" will match correctly.
- The normalization will standardizes different forms of the same character in Unicode. For example, CJK full-width numbers will be standardized to their ASCII forms.
- Ignorables such as Zero-Width Joiner and Variation Selectors are removed. These are typically modifier characters that affect display.
See Also
Normalizer2
FilteredNormalizer2
ICUNormalizer2Filter(TokenStream, Normalizer2)
Create a new ICUNormalizer2Filter with the specified ICU4N.Text.Normalizer2
Declaration
public ICUNormalizer2Filter(TokenStream input, Normalizer2 normalizer)Parameters
| Type | Name | Description |
|---|---|---|
| TokenStream | input | stream |
| Normalizer2 | normalizer | normalizer to use |
Remarks
With this filter, you can normalize text in the following ways:
- NFKC Normalization, Case Folding, and removing Ignorables (the default)
- Using a standard Normalization mode (NFC, NFD, NFKC, NFKD)
- Based on rules from a custom normalization mapping.
- The case folding that it does can be seen as a replacement for LowerCaseFilter: For example, it handles cases such as the Greek sigma, so that "Μάϊος" and "ΜΆΪΟΣ" will match correctly.
- The normalization will standardizes different forms of the same character in Unicode. For example, CJK full-width numbers will be standardized to their ASCII forms.
- Ignorables such as Zero-Width Joiner and Variation Selectors are removed. These are typically modifier characters that affect display.
See Also
Normalizer2
FilteredNormalizer2
Methods
IncrementToken()
Consumers (i.e., Lucene.Net.Index.IndexWriter) use this method to advance the stream to the next token. Implementing classes must implement this method and update the appropriate Lucene.Net.Util.IAttributes with the attributes of the next token.
The producer must make no assumptions about the attributes after the method has been returned: the caller may arbitrarily change it. If the producer needs to preserve the state for subsequent calls, it can use Lucene.Net.Util.AttributeSource.CaptureState() to create a copy of the current attribute state. this method is called for every token of a document, so an efficient implementation is crucial for good performance. To avoid calls to Lucene.Net.Util.AttributeSource.AddAttribute<T>() and Lucene.Net.Util.AttributeSource.GetAttribute<T>(), references to all Lucene.Net.Util.IAttributes that this stream uses should be retrieved during instantiation. To ensure that filters and consumers know which attributes are available, the attributes must be added during instantiation. Filters and consumers are not required to check for availability of attributes in Lucene.Net.Analysis.TokenStream.IncrementToken().Declaration
public override sealed bool IncrementToken()Returns
| Type | Description |
|---|---|
| bool | false for end of stream; true otherwise |
Overrides
Lucene.Net.Analysis.TokenStream.IncrementToken()
Remarks
With this filter, you can normalize text in the following ways:
- NFKC Normalization, Case Folding, and removing Ignorables (the default)
- Using a standard Normalization mode (NFC, NFD, NFKC, NFKD)
- Based on rules from a custom normalization mapping.
- The case folding that it does can be seen as a replacement for LowerCaseFilter: For example, it handles cases such as the Greek sigma, so that "Μάϊος" and "ΜΆΪΟΣ" will match correctly.
- The normalization will standardizes different forms of the same character in Unicode. For example, CJK full-width numbers will be standardized to their ASCII forms.
- Ignorables such as Zero-Width Joiner and Variation Selectors are removed. These are typically modifier characters that affect display.
See Also
Normalizer2
FilteredNormalizer2
Implements
See Also
Normalizer2
FilteredNormalizer2