public final class PositionFilter extends TokenFilter
AttributeSource.AttributeFactory, AttributeSource.State
input
Constructor and Description |
---|
PositionFilter(TokenStream input)
Constructs a PositionFilter that assigns a position increment of zero to
all but the first token from the given input stream.
|
PositionFilter(TokenStream input,
int positionIncrement)
Constructs a PositionFilter that assigns the given position increment to
all but the first token from the given input stream.
|
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()
Reset the filter as well as the input TokenStream.
|
close, end
addAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, copyTo, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, reflectAsString, reflectWith, restoreState, toString
public PositionFilter(TokenStream input)
input
- the input streampublic PositionFilter(TokenStream input, int positionIncrement)
input
- the input streampositionIncrement
- position increment to assign to all but the first
token from the input streampublic 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
reset
in class TokenFilter
IOException