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.
As of Lucene 4.4, an
IllegalArgumentException
is thrown when trying to disable position
increments when filtering terms.
AttributeSource.AttributeFactory, AttributeSource.State
Constructor and Description |
---|
FilteringTokenFilter(Version version,
boolean enablePositionIncrements,
TokenStream input)
Deprecated.
enablePositionIncrements=false is not supported anymore as of Lucene 4.4
|
FilteringTokenFilter(Version version,
TokenStream in)
Create a new
FilteringTokenFilter . |
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 |
getEnablePositionIncrements() |
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() . |
void |
setEnablePositionIncrements(boolean enable)
Deprecated.
enablePositionIncrements=false is not supported anymore as of Lucene 4.4
|
close
addAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, copyTo, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, reflectAsString, reflectWith, restoreState, toString
@Deprecated public FilteringTokenFilter(Version version, boolean enablePositionIncrements, TokenStream input)
FilteringTokenFilter
.version
- the Lucene match versionenablePositionIncrements
- whether to increment position increments when filtering out termsinput
- the input to consumepublic FilteringTokenFilter(Version version, TokenStream in)
FilteringTokenFilter
.version
- the Lucene match versionin
- the TokenStream
to consumepublic final boolean incrementToken() throws 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
IOException
public void reset() throws IOException
TokenFilter
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).
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 TokenFilter
IOException
public boolean getEnablePositionIncrements()
setEnablePositionIncrements(boolean)
@Deprecated public void setEnablePositionIncrements(boolean enable)
true
, this TokenFilter will preserve
positions of the incoming tokens (ie, accumulate and
set position increments of the removed tokens).
Generally, true
is best as it does not
lose information (positions of the original tokens)
during indexing.
When set, when a token is stopped (omitted), the position increment of the following token is incremented.
NOTE: be sure to also set org.apache.lucene.queryparser.classic.QueryParser#setEnablePositionIncrements if you use QueryParser to create queries.
public void end() throws IOException
TokenFilter
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()
.
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 TokenFilter
IOException
- If an I/O error occursCopyright © 2010 - 2020 Adobe. All Rights Reserved