org.apache.lucene.analysis
Class TeeSinkTokenFilter

java.lang.Object
  org.apache.lucene.util.AttributeSource
      org.apache.lucene.analysis.TokenStream
          org.apache.lucene.analysis.TokenFilter
              org.apache.lucene.analysis.TeeSinkTokenFilter

All Implemented Interfaces:

Closeable

public final class TeeSinkTokenFilter
extends TokenFilter

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.

Nested Class Summary

static class	TeeSinkTokenFilter.SinkFilter A filter that decides which AttributeSource states to store in the sink.
static class	TeeSinkTokenFilter.SinkTokenStream

Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource

AttributeSource.AttributeFactory, AttributeSource.State

Field Summary

Fields inherited from class org.apache.lucene.analysis.TokenFilter

input

Constructor Summary

TeeSinkTokenFilter(TokenStream input)
Instantiates a new TeeSinkTokenFilter.

Method Summary

void	addSinkTokenStream(TeeSinkTokenFilter.SinkTokenStream sink) Adds a TeeSinkTokenFilter.SinkTokenStream created by another TeeSinkTokenFilter to this one.
void	consumeAllTokens() TeeSinkTokenFilter passes all tokens to the added sinks when itself is consumed.
void	end() Performs end-of-stream operations, if any, and calls then end() on the input TokenStream. NOTE: Be sure to call super.end() first when overriding this method.
boolean	incrementToken() Consumers (i.e., IndexWriter) use this method to advance the stream to the next token.
TeeSinkTokenFilter.SinkTokenStream	newSinkTokenStream() Returns a new TeeSinkTokenFilter.SinkTokenStream that receives all tokens consumed by this stream.
TeeSinkTokenFilter.SinkTokenStream	newSinkTokenStream(TeeSinkTokenFilter.SinkFilter filter) Returns a new TeeSinkTokenFilter.SinkTokenStream that receives all tokens consumed by this stream that pass the supplied filter.

Methods inherited from class org.apache.lucene.analysis.TokenFilter

close, reset

Methods inherited from class org.apache.lucene.util.AttributeSource

addAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, copyTo, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, reflectAsString, reflectWith, restoreState, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

TeeSinkTokenFilter

public TeeSinkTokenFilter(TokenStream input)

Instantiates a new TeeSinkTokenFilter.

Method Detail

newSinkTokenStream

public TeeSinkTokenFilter.SinkTokenStream newSinkTokenStream()

Returns a new TeeSinkTokenFilter.SinkTokenStream that receives all tokens consumed by this stream.

newSinkTokenStream

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.

See Also:

TeeSinkTokenFilter.SinkFilter

addSinkTokenStream

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.

consumeAllTokens

public void consumeAllTokens()
                      throws 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, but all sinks are instant available.

Throws:

IOException

incrementToken

public boolean incrementToken()
                       throws IOException

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 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 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 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 TokenStream.incrementToken().

Specified by:

incrementToken in class TokenStream

Returns:

false for end of stream; true otherwise

Throws:

IOException

end

public final void end()
               throws IOException

Description copied from class: TokenFilter

Performs end-of-stream operations, if any, and calls then end() on the input TokenStream.

NOTE: Be sure to call super.end() first when overriding this method.

Overrides:

end in class TokenFilter

Throws:

IOException