public final class LimitTokenCountFilter extends TokenFilter
IndexWriter
.
By default, this filter ignores any tokens in the wrapped TokenStream
once the limit has been reached, which can result in reset()
being
called prior to incrementToken()
returning false
. For most
TokenStream
implementations this should be acceptable, and faster
then consuming the full stream. If you are wrapping a TokenStream
which requires that the full stream of tokens be exhausted in order to
function properly, use the
consumeAllTokens
option.
AttributeSource.AttributeFactory, AttributeSource.State
Constructor and Description |
---|
LimitTokenCountFilter(TokenStream in,
int maxTokenCount)
Build a filter that only accepts tokens up to a maximum number.
|
LimitTokenCountFilter(TokenStream in,
int maxTokenCount,
boolean consumeAllTokens)
Build an filter that limits the maximum number of tokens per field.
|
Modifier and Type | Method and Description |
---|---|
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() . |
close, end
addAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, copyTo, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, reflectAsString, reflectWith, restoreState, toString
public LimitTokenCountFilter(TokenStream in, int maxTokenCount)
public LimitTokenCountFilter(TokenStream in, int maxTokenCount, boolean consumeAllTokens)
in
- the stream to wrapmaxTokenCount
- max number of tokens to produceconsumeAllTokens
- whether all tokens from the input must be consumed even if maxTokenCount is reached.public 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
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