Analyzerpublic abstract class Analyzer extends Object | 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.
WARNING: You must override one of the methods defined by this class in your
subclass or the Analyzer will enter an infinite loop. |
| Methods Summary |
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| public int | getPositionIncrementGap(java.lang.String fieldName)Invoked before indexing a Field instance if
terms have already been added to that field. This allows custom
analyzers to place an automatic position increment gap between
Field 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 Field instances, are in successive positions, allowing
exact PhraseQuery matches, for instance, across Field instance boundaries.
return 0;
| | public abstract org.apache.lucene.analysis.TokenStream | tokenStream(java.lang.String fieldName, java.io.Reader reader)Creates a TokenStream which tokenizes all the text in the provided
Reader. Default implementation forwards to tokenStream(Reader) for
compatibility with older version. Override to allow Analyzer to choose
strategy based on document and/or field. Must be able to handle null
field name for backward compatibility.
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