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java.lang.Objectorg.apache.lucene.analysis.Analyzer
public abstract class Analyzer
An Analyzer builds TokenStreams, which analyze text. It thus represents a policy for extracting index terms from text.
In order to define what analysis is done, subclasses must define their
Analyzer.TokenStreamComponents
in createComponents(String, Reader)
.
The components are then reused in each call to tokenStream(String, Reader)
.
Nested Class Summary | |
---|---|
static class |
Analyzer.GlobalReuseStrategy
Implementation of Analyzer.ReuseStrategy that reuses the same components for
every field. |
static class |
Analyzer.PerFieldReuseStrategy
Implementation of Analyzer.ReuseStrategy that reuses components per-field by
maintaining a Map of TokenStreamComponent per field name. |
static class |
Analyzer.ReuseStrategy
Strategy defining how TokenStreamComponents are reused per call to tokenStream(String, java.io.Reader) . |
static class |
Analyzer.TokenStreamComponents
This class encapsulates the outer components of a token stream. |
Constructor Summary | |
---|---|
Analyzer()
|
|
Analyzer(Analyzer.ReuseStrategy reuseStrategy)
|
Method Summary | |
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void |
close()
Frees persistent resources used by this Analyzer |
protected abstract Analyzer.TokenStreamComponents |
createComponents(String fieldName,
Reader reader)
Creates a new Analyzer.TokenStreamComponents instance for this analyzer. |
int |
getOffsetGap(String fieldName)
Just like getPositionIncrementGap(java.lang.String) , except for
Token offsets instead. |
int |
getPositionIncrementGap(String fieldName)
Invoked before indexing a IndexableField instance if terms have already been added to that field. |
protected Reader |
initReader(String fieldName,
Reader reader)
Override this if you want to add a CharFilter chain. |
TokenStream |
tokenStream(String fieldName,
Reader reader)
Creates a TokenStream that is allowed to be re-use from the previous time that the same thread called this method. |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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public Analyzer()
public Analyzer(Analyzer.ReuseStrategy reuseStrategy)
Method Detail |
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protected abstract Analyzer.TokenStreamComponents createComponents(String fieldName, Reader reader)
Analyzer.TokenStreamComponents
instance for this analyzer.
fieldName
- the name of the fields content passed to the
Analyzer.TokenStreamComponents
sink as a readerreader
- the reader passed to the Tokenizer
constructor
Analyzer.TokenStreamComponents
for this analyzer.public final TokenStream tokenStream(String fieldName, Reader reader) throws IOException
This method uses createComponents(String, Reader)
to obtain an
instance of Analyzer.TokenStreamComponents
. It returns the sink of the
components and stores the components internally. Subsequent calls to this
method will reuse the previously stored components after resetting them
through Analyzer.TokenStreamComponents.setReader(Reader)
.
fieldName
- the name of the field the created TokenStream is used forreader
- the reader the streams source reads from
IOException
protected Reader initReader(String fieldName, Reader reader)
public int getPositionIncrementGap(String fieldName)
fieldName
- IndexableField name being indexed.
tokenStream(String,Reader)
public int getOffsetGap(String fieldName)
getPositionIncrementGap(java.lang.String)
, except for
Token offsets instead. By default this returns 1.
This method is only called if the field
produced at least one token for indexing.
fieldName
- the field just indexed
tokenStream(String,Reader)
public void close()
|
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