Class TeeSinkTokenFilter
- All Implemented Interfaces:
Closeable
,AutoCloseable
,Unwrappable<TokenStream>
It is also useful for doing things like entity extraction or proper noun analysis as part of the analysis workflow and saving off those tokens for use in another field.
TeeSinkTokenFilter source1 = new TeeSinkTokenFilter(new WhitespaceTokenizer()); TeeSinkTokenFilter.SinkTokenStream sink1 = source1.newSinkTokenStream(); TeeSinkTokenFilter.SinkTokenStream sink2 = source1.newSinkTokenStream(); TokenStream final1 = new LowerCaseFilter(source1); TokenStream final2 = new EntityDetect(sink1); TokenStream final3 = new URLDetect(sink2); d.add(new TextField("f1", final1)); d.add(new TextField("f2", final2)); d.add(new TextField("f3", final3));
In this example, sink1
and sink2
will both get tokens from source1
after whitespace tokenization, and will further do additional token filtering, e.g. detect
entities and URLs.
NOTE: it is important, that tees are consumed before sinks, therefore you should add
them to the document before the sinks. In the above example, f1 is added before the other
fields, and so by the time they are processed, it has already been consumed, which is the correct
way to index the three streams. If for some reason you cannot ensure that, you should call consumeAllTokens()
before adding the sinks to document fields.
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionstatic final class
TokenStream output from a tee.private static final class
A convenience wrapper for storing the cached states as well the final state of the stream.Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource
AttributeSource.State
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Field Summary
FieldsFields inherited from class org.apache.lucene.analysis.TokenFilter
input
Fields inherited from class org.apache.lucene.analysis.TokenStream
DEFAULT_TOKEN_ATTRIBUTE_FACTORY
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionvoid
TeeSinkTokenFilter
passes all tokens to the added sinks when itself is consumed.final void
end()
This method is called by the consumer after the last token has been consumed, afterTokenStream.incrementToken()
returnedfalse
(using the newTokenStream
API).boolean
Consumers (i.e.,IndexWriter
) use this method to advance the stream to the next token.Returns a newTeeSinkTokenFilter.SinkTokenStream
that receives all tokens consumed by this stream.void
reset()
This method is called by a consumer before it begins consumption usingTokenStream.incrementToken()
.Methods inherited from class org.apache.lucene.analysis.TokenFilter
close, unwrap
Methods inherited from class org.apache.lucene.util.AttributeSource
addAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, copyTo, endAttributes, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, reflectAsString, reflectWith, removeAllAttributes, restoreState, toString
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Field Details
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cachedStates
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Constructor Details
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TeeSinkTokenFilter
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Method Details
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newSinkTokenStream
Returns a newTeeSinkTokenFilter.SinkTokenStream
that receives all tokens consumed by this stream. -
consumeAllTokens
TeeSinkTokenFilter
passes all tokens to the added sinks when itself is consumed. To be sure that all tokens from the input stream are passed to the sinks, you can call this methods. This instance is exhausted after this method returns, but all sinks are instant available.- Throws:
IOException
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incrementToken
Description copied from class:TokenStream
Consumers (i.e.,IndexWriter
) use this method to advance the stream to the next token. Implementing classes must implement this method and update the appropriateAttributeImpl
s 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
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
AttributeSource.addAttribute(Class)
andAttributeSource.getAttribute(Class)
, references to allAttributeImpl
s 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
TokenStream.incrementToken()
.- Specified by:
incrementToken
in classTokenStream
- Returns:
- false for end of stream; true otherwise
- Throws:
IOException
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end
Description copied from class:TokenFilter
This method is called by the consumer after the last token has been consumed, afterTokenStream.incrementToken()
returnedfalse
(using the newTokenStream
API). Streams implementing the old API should upgrade to use this feature.This method can be used to perform any end-of-stream operations, such as setting the final offset of a stream. The final offset of a stream might differ from the offset of the last token eg in case one or more whitespaces followed after the last token, but a WhitespaceTokenizer was used.
Additionally any skipped positions (such as those removed by a stopfilter) can be applied to the position increment, or any adjustment of other attributes where the end-of-stream value may be important.
If you override this method, always call
super.end()
.NOTE: The default implementation chains the call to the input TokenStream, so be sure to call
super.end()
first when overriding this method.- Overrides:
end
in classTokenFilter
- Throws:
IOException
- If an I/O error occurs
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reset
Description copied from class:TokenFilter
This method is called by a consumer before it begins consumption usingTokenStream.incrementToken()
.Resets this stream to a clean state. Stateful implementations must implement this method so that they can be reused, just as if they had been created fresh.
If you override this method, always call
super.reset()
, otherwise some internal state will not be correctly reset (e.g.,Tokenizer
will throwIllegalStateException
on further usage).NOTE: The default implementation chains the call to the input TokenStream, so be sure to call
super.reset()
when overriding this method.- Overrides:
reset
in classTokenFilter
- Throws:
IOException
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