public final class TeeSinkTokenFilter extends TokenFilter
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.
Modifier and Type | Class and Description |
---|---|
static class |
TeeSinkTokenFilter.SinkTokenStream
TokenStream output from a tee.
|
private static class |
TeeSinkTokenFilter.States
A convenience wrapper for storing the cached states as well the final state of the stream.
|
AttributeSource.State
Modifier and Type | Field and Description |
---|---|
private TeeSinkTokenFilter.States |
cachedStates |
input
DEFAULT_TOKEN_ATTRIBUTE_FACTORY
Constructor and Description |
---|
TeeSinkTokenFilter(TokenStream input) |
Modifier and Type | Method and Description |
---|---|
void |
consumeAllTokens()
TeeSinkTokenFilter passes all tokens to the added sinks when itself is consumed. |
void |
end()
This method is called by the consumer after the last token has been
consumed, after
TokenStream.incrementToken() returned false
(using the new TokenStream API). |
boolean |
incrementToken()
Consumers (i.e.,
IndexWriter ) use this method to advance the stream to
the next token. |
TokenStream |
newSinkTokenStream()
Returns a new
TeeSinkTokenFilter.SinkTokenStream that receives all tokens consumed by this stream. |
void |
reset()
This method is called by a consumer before it begins consumption using
TokenStream.incrementToken() . |
close
addAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, copyTo, endAttributes, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, reflectAsString, reflectWith, removeAllAttributes, restoreState, toString
private final TeeSinkTokenFilter.States cachedStates
public TeeSinkTokenFilter(TokenStream input)
public TokenStream newSinkTokenStream()
TeeSinkTokenFilter.SinkTokenStream
that receives all tokens consumed by this stream.public void consumeAllTokens() throws java.io.IOException
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.java.io.IOException
public boolean incrementToken() throws java.io.IOException
TokenStream
IndexWriter
) use this method to advance the stream to
the next token. Implementing classes must implement this method and update
the appropriate AttributeImpl
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)
and AttributeSource.getAttribute(Class)
,
references to all AttributeImpl
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()
.
incrementToken
in class TokenStream
java.io.IOException
public final void end() throws java.io.IOException
TokenFilter
TokenStream.incrementToken()
returned false
(using the new TokenStream
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.
end
in class TokenFilter
java.io.IOException
- If an I/O error occurspublic void reset() throws java.io.IOException
TokenFilter
TokenStream.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
throw IllegalStateException
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.
reset
in class TokenFilter
java.io.IOException