public final class StandardTokenizer extends Tokenizer
This class implements the Word Break rules from the Unicode Text Segmentation algorithm, as specified in Unicode Standard Annex #29.
Many applications have specific tokenizer needs. If this tokenizer does not suit your application, please consider copying this source code directory to your project and maintaining your own grammar-based tokenizer.
AttributeSource.State
Modifier and Type | Field and Description |
---|---|
static int |
ALPHANUM
Alpha/numeric token type
|
static int |
EMOJI
Emoji token type.
|
static int |
HANGUL
Hangul token type
|
static int |
HIRAGANA
Hiragana token type
|
static int |
IDEOGRAPHIC
Ideographic token type
|
static int |
KATAKANA
Katakana token type
|
static int |
MAX_TOKEN_LENGTH_LIMIT
Absolute maximum sized token
|
static int |
NUM
Numeric token type
|
static int |
SOUTHEAST_ASIAN
Southeast Asian token type
|
static String[] |
TOKEN_TYPES
String token types that correspond to token type int constants
|
DEFAULT_TOKEN_ATTRIBUTE_FACTORY
Constructor and Description |
---|
StandardTokenizer()
Creates a new instance of the
StandardTokenizer . |
StandardTokenizer(AttributeFactory factory)
Creates a new StandardTokenizer with a given
AttributeFactory |
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). |
int |
getMaxTokenLength()
Returns the current maximum token length
|
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 |
setMaxTokenLength(int length)
Set the max allowed token length.
|
correctOffset, setReader
addAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, copyTo, endAttributes, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, reflectAsString, reflectWith, removeAllAttributes, restoreState, toString
public static final int ALPHANUM
public static final int NUM
public static final int SOUTHEAST_ASIAN
public static final int IDEOGRAPHIC
public static final int HIRAGANA
public static final int KATAKANA
public static final int HANGUL
public static final int EMOJI
public static final String[] TOKEN_TYPES
public static final int MAX_TOKEN_LENGTH_LIMIT
public StandardTokenizer()
StandardTokenizer
. Attaches
the input
to the newly created JFlex scanner.
See http://issues.apache.org/jira/browse/LUCENE-1068public StandardTokenizer(AttributeFactory factory)
AttributeFactory
public void setMaxTokenLength(int length)
LengthFilter
to remove long tokens. The default is
StandardAnalyzer.DEFAULT_MAX_TOKEN_LENGTH
.IllegalArgumentException
- if the given length is outside of the
range [1, 1048576].public int getMaxTokenLength()
setMaxTokenLength(int)
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 final 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.
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()
.
end
in class TokenStream
IOException
- If an I/O error occurspublic void close() throws IOException
Tokenizer
If you override this method, always call super.close()
, otherwise
some internal state will not be correctly reset (e.g., Tokenizer
will
throw IllegalStateException
on reuse).
NOTE:
The default implementation closes the input Reader, so
be sure to call super.close()
when overriding this method.
close
in interface Closeable
close
in interface AutoCloseable
close
in class Tokenizer
IOException
public void reset() throws IOException
TokenStream
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).
reset
in class Tokenizer
IOException
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