public class TeeTokenFilter
- extends TokenFilter
Works in conjunction with the SinkTokenizer to provide the ability to set aside tokens
that have already been analyzed. This is useful in situations where multiple fields share
many common analysis steps and then go their separate ways.
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.
SinkTokenizer sink1 = new SinkTokenizer();
SinkTokenizer sink2 = new SinkTokenizer();
TokenStream source1 = new TeeTokenFilter(new TeeTokenFilter(new WhitespaceTokenizer(reader1), sink1), sink2);
TokenStream source2 = new TeeTokenFilter(new TeeTokenFilter(new WhitespaceTokenizer(reader2), sink1), sink2);
TokenStream final1 = new LowerCaseFilter(source1);
TokenStream final2 = source2;
TokenStream final3 = new EntityDetect(sink1);
TokenStream final4 = new URLDetect(sink2);
d.add(new Field("f1", final1));
d.add(new Field("f2", final2));
d.add(new Field("f3", final3));
d.add(new Field("f4", final4));
In this example,
will both get tokens from both
reader2 after whitespace tokenizer
and now we can further wrap any of these in extra analysis, and more "sources" can be inserted if desired.
It is important, that tees are consumed before sinks (in the above example, the field names must be
less the sink's field names).
Note, the EntityDetect and URLDetect TokenStreams are for the example and do not currently exist in Lucene
SinkTokenizer only work with the old TokenStream API.
If you switch to the new API, you need to use
TeeSinkTokenFilter instead, which offers
the same functionality.
- See Also:
Deprecated. Returns the next token in the stream, or null at EOS.
|Methods inherited from class org.apache.lucene.util.AttributeSource
addAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, restoreState, toString
public TeeTokenFilter(TokenStream input,
public Token next(Token reusableToken)
- Description copied from class:
- Returns the next token in the stream, or null at EOS. When possible, the
input Token should be used as the returned Token (this gives fastest
tokenization performance), but this is not required and a new Token may be
returned. Callers may re-use a single Token instance for successive calls
to this method.
This implicitly defines a "contract" between consumers (callers of this
method) and producers (implementations of this method that are the source
Also, the producer must make no assumptions about a
- A consumer must fully consume the previously returned
before calling this method again.
- A producer must call
Token.clear() before setting the fields in
it and returning it
Token after it
has been returned: the caller may arbitrarily change it. If the producer
needs to hold onto the
Token for subsequent calls, it must clone()
it before storing it. Note that a
TokenFilter is considered a
next in class
reusableToken - a
Token that may or may not be used to return;
this parameter should never be null (the callee is not required to
check for null before using it, but it is a good idea to assert that
it is not null.)
Token in the stream or null if end-of-stream was hit
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