public final class ConcatenatingTokenStream extends TokenStream
AttributeSource.State
Modifier and Type | Field and Description |
---|---|
private int |
currentSource |
private int |
initialPositionIncrement |
private OffsetAttribute |
offsetAtt |
private int |
offsetIncrement |
private PositionIncrementAttribute |
posIncAtt |
private PositionIncrementAttribute[] |
sourceIncrements |
private OffsetAttribute[] |
sourceOffsets |
private TokenStream[] |
sources |
DEFAULT_TOKEN_ATTRIBUTE_FACTORY
Constructor and Description |
---|
ConcatenatingTokenStream(TokenStream... sources)
Create a new ConcatenatingTokenStream from a set of inputs
|
Modifier and Type | Method and Description |
---|---|
void |
close()
Releases resources associated with this stream.
|
private static AttributeSource |
combineSources(TokenStream... sources) |
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. |
void |
reset()
This method is called by a consumer before it begins consumption using
TokenStream.incrementToken() . |
addAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, copyTo, endAttributes, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, reflectAsString, reflectWith, removeAllAttributes, restoreState, toString
private final TokenStream[] sources
private final OffsetAttribute[] sourceOffsets
private final PositionIncrementAttribute[] sourceIncrements
private final OffsetAttribute offsetAtt
private final PositionIncrementAttribute posIncAtt
private int currentSource
private int offsetIncrement
private int initialPositionIncrement
public ConcatenatingTokenStream(TokenStream... sources)
sources
- an array of TokenStream inputs to concatenateprivate static AttributeSource combineSources(TokenStream... sources)
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 void end() throws java.io.IOException
TokenStream
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()
.
end
in class TokenStream
java.io.IOException
- If an I/O error occurspublic void reset() throws java.io.IOException
TokenStream
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).
reset
in class TokenStream
java.io.IOException
public void close() throws java.io.IOException
TokenStream
If you override this method, always call super.close()
, otherwise
some internal state will not be correctly reset (e.g., Tokenizer
will
throw IllegalStateException
on reuse).
close
in interface java.io.Closeable
close
in interface java.lang.AutoCloseable
close
in class TokenStream
java.io.IOException