public final class JapaneseTokenizer extends Tokenizer
This tokenizer sets a number of additional attributes:
BaseFormAttributecontaining base form for inflected adjectives and verbs.
ReadingAttributecontaining reading and pronunciation.
InflectionAttributecontaining additional part-of-speech information for inflected forms.
This tokenizer uses a rolling Viterbi search to find the
least cost segmentation (path) of the incoming characters.
For tokens that appear to be compound (> length 2 for all
Kanji, or > length 7 for non-Kanji), we see if there is a
2nd best segmentation of that token after applying
penalties to the long tokens. If so, and the Mode is
JapaneseTokenizer.Mode.SEARCH, we output the alternate segmentation
|Modifier and Type||Class and Description|
Tokenization mode: this determines how the tokenizer handles compound and unknown words.
|Modifier and Type||Field and Description|
Default tokenization mode.
|Constructor and Description|
Create a new JapaneseTokenizer.
|Modifier and Type||Method and Description|
This method is called by the consumer after the last token has been consumed, after
Resets this stream to the beginning.
Expert: Reset the tokenizer to a new reader.
Expert: set this to produce graphviz (dot) output of the Viterbi lattice
addAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, copyTo, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, reflectAsString, reflectWith, restoreState, toString
public static final JapaneseTokenizer.Mode DEFAULT_MODE
public JapaneseTokenizer(Reader input, UserDictionary userDictionary, boolean discardPunctuation, JapaneseTokenizer.Mode mode)
input- Reader containing text
userDictionary- Optional: if non-null, user dictionary.
discardPunctuation- true if punctuation tokens should be dropped from the output.
mode- tokenization mode.
public void setGraphvizFormatter(GraphvizFormatter dotOut)
public void reset(Reader input) throws IOException
public void reset() throws IOException
TokenStream.reset()is not needed for the standard indexing process. However, if the tokens of a
TokenStreamare 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
public void end()
false(using the new
TokenStreamAPI). 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
public boolean incrementToken() throws IOException
IndexWriter) use this method to advance the stream to the next token. Implementing classes must implement this method and update the appropriate
AttributeImpls 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
references to all
AttributeImpls 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