Class Analyzer

An Analyzer builds TokenStreams, which analyze text. It thus represents a policy for extracting index terms from text.

Typical implementations first build a Tokenizer, which breaks the stream of characters from the Reader into raw Tokens. One or more TokenFilters may then be applied to the output of the Tokenizer.

Inheritance

System.Object

Analyzer

KeywordAnalyzer

PerFieldAnalyzerWrapper

SimpleAnalyzer

StopAnalyzer

WhitespaceAnalyzer

Namespace:

Assembly: Lucene.Net.NetCore.dll

Syntax

public abstract class Analyzer : IDisposable

Fields

Name	Description
overridesTokenStreamMethod

Properties

Name	Description
PreviousTokenStream	Used by Analyzers that implement reusableTokenStream to retrieve previously saved TokenStreams for re-use by the same thread.

Methods

Name	Description
Close()	Frees persistent resources used by this Analyzer
Dispose()
Dispose(Boolean)
GetOffsetGap(IFieldable)	Just like GetPositionIncrementGap(String), except for Token offsets instead. By default this returns 1 for tokenized fields and, as if the fields were joined with an extra space character, and 0 for un-tokenized fields. This method is only called if the field produced at least one token for indexing.
GetPositionIncrementGap(String)	Invoked before indexing a Fieldable instance if terms have already been added to that field. This allows custom analyzers to place an automatic position increment gap between Fieldable instances using the same field name. The default value position increment gap is 0. With a 0 position increment gap and the typical default token position increment of 1, all terms in a field, including across Fieldable instances, are in successive positions, allowing exact PhraseQuery matches, for instance, across Fieldable instance boundaries.
ReusableTokenStream(String, IO.TextReader)	Creates a TokenStream that is allowed to be re-used from the previous time that the same thread called this method. Callers that do not need to use more than one TokenStream at the same time from this analyzer should use this method for better performance.
SetOverridesTokenStreamMethod<TClass>()	Java uses Class<? extends Analyer> to constrain `TClass` to only Types that inherit from Analyzer. C# does not have a generic type class, ie Type<t>. The method signature stays the same, and an exception may still be thrown, if the method doesn't exist.
TokenStream(String, IO.TextReader)	Creates a TokenStream which tokenizes all the text in the provided Reader. Must be able to handle null field name for backward compatibility.