public final class CachingTokenFilter extends TokenFilter
CachingTokenFilter implements the optional method
TokenStream.reset(), which repositions the
stream to the first Token.
AttributeSource.AttributeFactory, AttributeSource.Stateinput| Constructor and Description |
|---|
CachingTokenFilter(TokenStream input)
Create a new CachingTokenFilter around
input,
caching its token attributes, which can be replayed again
after a call to reset(). |
| Modifier and Type | Method and Description |
|---|---|
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()
Rewinds the iterator to the beginning of the cached list.
|
closeaddAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, copyTo, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, reflectAsString, reflectWith, restoreState, toStringpublic CachingTokenFilter(TokenStream input)
input,
caching its token attributes, which can be replayed again
after a call to reset().public final boolean incrementToken()
throws IOException
TokenStreamIndexWriter) 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().
incrementToken in class TokenStreamIOExceptionpublic final void end()
TokenFilterTokenStream.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 TokenFilterpublic void reset()
Note that this does not call reset() on the wrapped tokenstream ever, even the first time. You should reset() the inner tokenstream before wrapping it with CachingTokenFilter.
reset in class TokenFilterCopyright © 2000-2014 Apache Software Foundation. All Rights Reserved.