public class PrefixAwareTokenFilter extends TokenStream
AttributeSource.AttributeFactory, AttributeSource.State
Constructor and Description |
---|
PrefixAwareTokenFilter(TokenStream prefix,
TokenStream suffix) |
Modifier and Type | Method and Description |
---|---|
void |
close()
Releases resources associated with this stream.
|
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). |
TokenStream |
getPrefix() |
TokenStream |
getSuffix() |
boolean |
incrementToken()
Consumers (i.e.,
IndexWriter ) use this method to advance the stream to
the next token. |
void |
reset()
Resets this stream to the beginning.
|
void |
setPrefix(TokenStream prefix) |
void |
setSuffix(TokenStream suffix) |
Token |
updateSuffixToken(Token suffixToken,
Token lastPrefixToken)
The default implementation adds last prefix token end offset to the suffix token start and end offsets.
|
addAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, copyTo, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, reflectAsString, reflectWith, restoreState, toString
public PrefixAwareTokenFilter(TokenStream prefix, TokenStream suffix)
public 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 Token updateSuffixToken(Token suffixToken, Token lastPrefixToken)
suffixToken
- a token from the suffix streamlastPrefixToken
- the last token from the prefix streampublic void end() throws 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.end
in class TokenStream
IOException
public void close() throws IOException
TokenStream
close
in interface Closeable
close
in class TokenStream
IOException
public void reset() throws IOException
TokenStream
TokenStream.reset()
is not needed for
the standard indexing process. However, if the tokens of a
TokenStream
are intended to be consumed more than once, it is
necessary to implement TokenStream.reset()
. Note that if your TokenStream
caches tokens and feeds them back again after a reset, it is imperative
that you clone the tokens when you store them away (on the first pass) as
well as when you return them (on future passes after TokenStream.reset()
).reset
in class TokenStream
IOException
public TokenStream getPrefix()
public void setPrefix(TokenStream prefix)
public TokenStream getSuffix()
public void setSuffix(TokenStream suffix)