| java.lang.Object | ||||
| ↳ | org.apache.lucene.util.AttributeSource | |||
| ↳ | org.apache.lucene.analysis.TokenStream | |||
| ↳ | org.apache.lucene.analysis.TokenFilter | |||
| ↳ | org.apache.lucene.analysis.TeeSinkTokenFilter | |||
Class Overview
This TokenFilter provides the ability to set aside attribute states 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.
TeeSinkTokenFilter source1 = new TeeSinkTokenFilter(new WhitespaceTokenizer(reader1));
TeeSinkTokenFilter.SinkTokenStream sink1 = source1.newSinkTokenStream();
TeeSinkTokenFilter.SinkTokenStream sink2 = source1.newSinkTokenStream();
TeeSinkTokenFilter source2 = new TeeSinkTokenFilter(new WhitespaceTokenizer(reader2));
source2.addSinkTokenStream(sink1);
source2.addSinkTokenStream(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, sink1 and sink2 will both get tokens from both
reader1 and 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). If you are not sure, which stream is consumed first, you can simply
add another sink and then pass all tokens to the sinks at once using consumeAllTokens().
This TokenFilter is exhausted after this. In the above example, change
the example above to:
... TokenStream final1 = new LowerCaseFilter(source1.newSinkTokenStream()); TokenStream final2 = source2.newSinkTokenStream(); sink1.consumeAllTokens(); sink2.consumeAllTokens(); ...In this case, the fields can be added in any order, because the sources are not used anymore and all sinks are ready.
Note, the EntityDetect and URLDetect TokenStreams are for the example and do not currently exist in Lucene.
Summary
| Nested Classes | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| TeeSinkTokenFilter.SinkFilter | A filter that decides which AttributeSource states to store in the sink. |
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| TeeSinkTokenFilter.SinkTokenStream | |||||||||||
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[Expand]
Inherited Fields | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
 From class
org.apache.lucene.analysis.TokenFilter
| |||||||||||
| Public Constructors | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Instantiates a new TeeSinkTokenFilter.
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| Public Methods | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Adds a
TeeSinkTokenFilter.SinkTokenStream created by another TeeSinkTokenFilter
to this one. | |||||||||||
TeeSinkTokenFilter passes all tokens to the added sinks
when itself is consumed. | |||||||||||
Performs end-of-stream operations, if any, and calls then
end() on the
input TokenStream. | |||||||||||
Consumers (i.e.,
IndexWriter) use this method to advance the stream to
the next token. | |||||||||||
Returns a new
TeeSinkTokenFilter.SinkTokenStream that receives all tokens consumed by this stream. | |||||||||||
Returns a new
TeeSinkTokenFilter.SinkTokenStream that receives all tokens consumed by this stream
that pass the supplied filter. | |||||||||||
|
[Expand]
Inherited Methods | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
|
From class
org.apache.lucene.analysis.TokenFilter
| |||||||||||
|
From class
org.apache.lucene.analysis.TokenStream
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From class
org.apache.lucene.util.AttributeSource
| |||||||||||
|
From class
java.lang.Object
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From interface
java.io.Closeable
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Public Constructors
Public Methods
public void addSinkTokenStream (TeeSinkTokenFilter.SinkTokenStream sink)
Adds a TeeSinkTokenFilter.SinkTokenStream created by another TeeSinkTokenFilter
to this one. The supplied stream will also receive all consumed tokens.
This method can be used to pass tokens from two different tees to one sink.
public void 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, but all sinks are instant available.
Throws
| IOException |
|---|
public final void end ()
Performs end-of-stream operations, if any, and calls then end() on the
input TokenStream.
super.end() first when overriding this method.Throws
| IOException |
|---|
public boolean incrementToken ()
Consumers (i.e., IndexWriter) use this method to advance the stream to
the next token. Implementing classes must implement this method and update
the appropriate AttributeImpls 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
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
addAttribute(Class) and getAttribute(Class),
references to all AttributeImpls 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
incrementToken().
Returns
- false for end of stream; true otherwise
Throws
| IOException |
|---|
public TeeSinkTokenFilter.SinkTokenStream newSinkTokenStream ()
Returns a new TeeSinkTokenFilter.SinkTokenStream that receives all tokens consumed by this stream.
public TeeSinkTokenFilter.SinkTokenStream newSinkTokenStream (TeeSinkTokenFilter.SinkFilter filter)
Returns a new TeeSinkTokenFilter.SinkTokenStream that receives all tokens consumed by this stream
that pass the supplied filter.