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    Class WordDelimiterFilter

    Splits words into subwords and performs optional transformations on subword groups. Words are split into subwords with the following rules:

    • split on intra-word delimiters (by default, all non alpha-numeric characters): "Wi-Fi" → "Wi", "Fi"
    • split on case transitions: "PowerShot" → "Power", "Shot"
    • split on letter-number transitions: "SD500" → "SD", "500"
    • leading and trailing intra-word delimiters on each subword are ignored: "//hello---there, 'dude'" → "hello", "there", "dude"
    • trailing "'s" are removed for each subword: "O'Neil's" → "O", "Neil"
        Note: this step isn't performed in a separate filter because of possible subword combinations.

    The combinations parameter affects how subwords are combined:

    • combinations="0" causes no subword combinations:
      "PowerShot"
      → 0:"Power", 1:"Shot" (0 and 1 are the token positions)
    • combinations="1" means that in addition to the subwords, maximum runs of non-numeric subwords are catenated and produced at the same position of the last subword in the run:
        "PowerShot" → 0:"Power", 1:"Shot" 1:"PowerShot" "A's+B's&C's" -gt; 0:"A", 1:"B", 2:"C", 2:"ABC" "Super-Duper-XL500-42-AutoCoder!" → 0:"Super", 1:"Duper", 2:"XL", 2:"SuperDuperXL", 3:"500" 4:"42", 5:"Auto", 6:"Coder", 6:"AutoCoder"

    One use for WordDelimiterFilter is to help match words with different subword delimiters. For example, if the source text contained "wi-fi" one may want "wifi" "WiFi" "wi-fi" "wi+fi" queries to all match. One way of doing so is to specify combinations="1" in the analyzer used for indexing, and combinations="0" (the default) in the analyzer used for querying. Given that the current StandardTokenizer immediately removes many intra-word delimiters, it is recommended that this filter be used after a tokenizer that does not do this (such as WhitespaceTokenizer).

    Inheritance
    System.Object
    AttributeSource
    TokenStream
    TokenFilter
    WordDelimiterFilter
    Implements
    IDisposable
    Inherited Members
    TokenFilter.m_input
    TokenFilter.End()
    TokenFilter.Dispose(Boolean)
    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.Equals(Object)
    AttributeSource.ReflectAsString(Boolean)
    AttributeSource.ReflectWith(IAttributeReflector)
    AttributeSource.CloneAttributes()
    AttributeSource.CopyTo(AttributeSource)
    AttributeSource.ToString()
    Namespace: Lucene.Net.Analysis.Miscellaneous
    Assembly: Lucene.Net.Analysis.Common.dll
    Syntax
    public sealed class WordDelimiterFilter : TokenFilter, IDisposable

    Constructors

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    WordDelimiterFilter(LuceneVersion, TokenStream, WordDelimiterFlags, CharArraySet)

    Creates a new WordDelimiterFilter using DEFAULT_WORD_DELIM_TABLE as its charTypeTable

    Declaration
    public WordDelimiterFilter(LuceneVersion matchVersion, TokenStream in, WordDelimiterFlags configurationFlags, CharArraySet protWords)
    Parameters
    Type Name Description
    LuceneVersion matchVersion

    lucene compatibility version

    TokenStream in

    TokenStream to be filtered

    WordDelimiterFlags configurationFlags

    Flags configuring the filter

    CharArraySet protWords

    If not null is the set of tokens to protect from being delimited

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    WordDelimiterFilter(LuceneVersion, TokenStream, Byte[], WordDelimiterFlags, CharArraySet)

    Creates a new WordDelimiterFilter

    Declaration
    public WordDelimiterFilter(LuceneVersion matchVersion, TokenStream in, byte[] charTypeTable, WordDelimiterFlags configurationFlags, CharArraySet protWords)
    Parameters
    Type Name Description
    LuceneVersion matchVersion

    lucene compatibility version

    TokenStream in

    TokenStream to be filtered

    System.Byte[] charTypeTable

    table containing character types

    WordDelimiterFlags configurationFlags

    Flags configuring the filter

    CharArraySet protWords

    If not null is the set of tokens to protect from being delimited

    Fields

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    ALPHA

    Declaration
    public const int ALPHA = null
    Field Value
    Type Description
    System.Int32
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    ALPHANUM

    Declaration
    public const int ALPHANUM = null
    Field Value
    Type Description
    System.Int32
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    DIGIT

    Declaration
    public const int DIGIT = null
    Field Value
    Type Description
    System.Int32
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    LOWER

    Declaration
    public const int LOWER = null
    Field Value
    Type Description
    System.Int32
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    SUBWORD_DELIM

    Declaration
    public const int SUBWORD_DELIM = null
    Field Value
    Type Description
    System.Int32
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    UPPER

    Declaration
    public const int UPPER = null
    Field Value
    Type Description
    System.Int32

    Methods

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    IncrementToken()

    Declaration
    public override bool IncrementToken()
    Returns
    Type Description
    System.Boolean
    Overrides
    TokenStream.IncrementToken()
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    Reset()

    Declaration
    public override void Reset()
    Overrides
    TokenFilter.Reset()

    Implements

    IDisposable
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