public abstract class FilteringTokenFilter extends TokenFilter
accept() and return a boolean if the current
token should be preserved. incrementToken() uses this method
to decide if a token should be passed to the caller.AttributeSource.StateinputDEFAULT_TOKEN_ATTRIBUTE_FACTORY| Constructor and Description |
|---|
FilteringTokenFilter(TokenStream in)
Create a new
FilteringTokenFilter. |
| Modifier and Type | Method and Description |
|---|---|
protected abstract boolean |
accept()
Override this method and return if the current input token should be returned by
incrementToken(). |
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(). |
closeaddAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, copyTo, endAttributes, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, reflectAsString, reflectWith, removeAllAttributes, restoreState, toStringpublic FilteringTokenFilter(TokenStream in)
FilteringTokenFilter.in - the TokenStream to consumeprotected abstract boolean accept()
throws IOException
incrementToken().IOExceptionpublic 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 void reset()
throws IOException
TokenFilterTokenStream.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).
NOTE:
The default implementation chains the call to the input TokenStream, so
be sure to call super.reset() when overriding this method.
reset in class TokenFilterIOExceptionpublic void end()
throws IOException
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 TokenFilterIOException - If an I/O error occursCopyright © 2000-2018 Apache Software Foundation. All Rights Reserved.