public final class EdgeNGramTokenFilter extends TokenFilter
This TokenFilter
create n-grams from the beginning edge or ending edge of a input token.
Modifier and Type | Class and Description |
---|---|
static class |
EdgeNGramTokenFilter.Side
Specifies which side of the input the n-gram should be generated from
|
AttributeSource.AttributeFactory, AttributeSource.State
Modifier and Type | Field and Description |
---|---|
static int |
DEFAULT_MAX_GRAM_SIZE |
static int |
DEFAULT_MIN_GRAM_SIZE |
static EdgeNGramTokenFilter.Side |
DEFAULT_SIDE |
input
Constructor and Description |
---|
EdgeNGramTokenFilter(TokenStream input,
EdgeNGramTokenFilter.Side side,
int minGram,
int maxGram)
Creates EdgeNGramTokenFilter that can generate n-grams in the sizes of the given range
|
EdgeNGramTokenFilter(TokenStream input,
String sideLabel,
int minGram,
int maxGram)
Creates EdgeNGramTokenFilter that can generate n-grams in the sizes of the given range
|
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 static final EdgeNGramTokenFilter.Side DEFAULT_SIDE
public static final int DEFAULT_MAX_GRAM_SIZE
public static final int DEFAULT_MIN_GRAM_SIZE
public EdgeNGramTokenFilter(TokenStream input, EdgeNGramTokenFilter.Side side, int minGram, int maxGram)
input
- TokenStream
holding the input to be tokenizedside
- the EdgeNGramTokenFilter.Side
from which to chop off an n-gramminGram
- the smallest n-gram to generatemaxGram
- the largest n-gram to generatepublic EdgeNGramTokenFilter(TokenStream input, String sideLabel, int minGram, int maxGram)
input
- TokenStream
holding the input to be tokenizedsideLabel
- the name of the EdgeNGramTokenFilter.Side
from which to chop off an n-gramminGram
- the smallest n-gram to generatemaxGram
- the largest n-gram to generatepublic 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