- java.lang.Object
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- org.apache.lucene.util.AttributeSource
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- org.apache.lucene.analysis.TokenStream
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- org.apache.lucene.analysis.Tokenizer
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- org.apache.lucene.analysis.ko.KoreanTokenizer
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- All Implemented Interfaces:
java.io.Closeable
,java.lang.AutoCloseable
public final class KoreanTokenizer extends Tokenizer
Tokenizer for Korean that uses morphological analysis.This tokenizer sets a number of additional attributes:
PartOfSpeechAttribute
containing part-of-speech.ReadingAttribute
containing reading.
This tokenizer uses a rolling Viterbi search to find the least cost segmentation (path) of the incoming characters.
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Nested Class Summary
Nested Classes Modifier and Type Class Description static class
KoreanTokenizer.DecompoundMode
Decompound mode: this determines how the tokenizer handlesPOS.Type.COMPOUND
,POS.Type.INFLECT
andPOS.Type.PREANALYSIS
tokens.(package private) static class
KoreanTokenizer.Position
static class
KoreanTokenizer.Type
Token type reflecting the original source of this token(package private) static class
KoreanTokenizer.WrappedPositionArray
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Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource
AttributeSource.State
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Field Summary
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Fields inherited from class org.apache.lucene.analysis.TokenStream
DEFAULT_TOKEN_ATTRIBUTE_FACTORY
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Constructor Summary
Constructors Constructor Description KoreanTokenizer()
Creates a new KoreanTokenizer with default parameters.KoreanTokenizer(AttributeFactory factory, TokenInfoDictionary systemDictionary, UnknownDictionary unkDictionary, ConnectionCosts connectionCosts, UserDictionary userDictionary, KoreanTokenizer.DecompoundMode mode, boolean outputUnknownUnigrams, boolean discardPunctuation)
Create a new KoreanTokenizer supplying a custom system dictionary and unknown dictionary.KoreanTokenizer(AttributeFactory factory, UserDictionary userDictionary, KoreanTokenizer.DecompoundMode mode, boolean outputUnknownUnigrams)
Create a new KoreanTokenizer using the system and unknown dictionaries shipped with Lucene.KoreanTokenizer(AttributeFactory factory, UserDictionary userDictionary, KoreanTokenizer.DecompoundMode mode, boolean outputUnknownUnigrams, boolean discardPunctuation)
Create a new KoreanTokenizer using the system and unknown dictionaries shipped with Lucene.
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description private void
add(Dictionary dict, KoreanTokenizer.Position fromPosData, int wordPos, int endPos, int wordID, KoreanTokenizer.Type type)
private void
backtrace(KoreanTokenizer.Position endPosData, int fromIDX)
void
close()
Releases resources associated with this stream.private int
computeSpacePenalty(POS.Tag leftPOS, int numSpaces)
Returns the space penalty associated with the providedPOS.Tag
.void
end()
This method is called by the consumer after the last token has been consumed, afterTokenStream.incrementToken()
returnedfalse
(using the newTokenStream
API).(package private) Dictionary
getDict(KoreanTokenizer.Type type)
boolean
incrementToken()
Consumers (i.e.,IndexWriter
) use this method to advance the stream to the next token.private static boolean
isCommonOrInherited(java.lang.Character.UnicodeScript script)
private static boolean
isPunctuation(char ch)
private static boolean
isPunctuation(char ch, int cid)
private static boolean
isSameScript(java.lang.Character.UnicodeScript scriptOne, java.lang.Character.UnicodeScript scriptTwo)
Determine if two scripts are compatible.private void
parse()
void
reset()
This method is called by a consumer before it begins consumption usingTokenStream.incrementToken()
.private void
resetState()
void
setGraphvizFormatter(GraphvizFormatter dotOut)
Expert: set this to produce graphviz (dot) output of the Viterbi latticeprivate boolean
shouldFilterToken(Token token)
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Methods inherited from class org.apache.lucene.analysis.Tokenizer
correctOffset, setReader, setReaderTestPoint
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Methods inherited from class org.apache.lucene.util.AttributeSource
addAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, copyTo, endAttributes, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, reflectAsString, reflectWith, removeAllAttributes, restoreState, toString
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Field Detail
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DEFAULT_DECOMPOUND
public static final KoreanTokenizer.DecompoundMode DEFAULT_DECOMPOUND
Default mode for the decompound of tokens (KoreanTokenizer.DecompoundMode.DISCARD
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VERBOSE
private static final boolean VERBOSE
- See Also:
- Constant Field Values
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MAX_UNKNOWN_WORD_LENGTH
private static final int MAX_UNKNOWN_WORD_LENGTH
- See Also:
- Constant Field Values
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MAX_BACKTRACE_GAP
private static final int MAX_BACKTRACE_GAP
- See Also:
- Constant Field Values
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dictionaryMap
private final java.util.EnumMap<KoreanTokenizer.Type,Dictionary> dictionaryMap
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fst
private final TokenInfoFST fst
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dictionary
private final TokenInfoDictionary dictionary
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unkDictionary
private final UnknownDictionary unkDictionary
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costs
private final ConnectionCosts costs
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userDictionary
private final UserDictionary userDictionary
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characterDefinition
private final CharacterDefinition characterDefinition
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arc
private final FST.Arc<java.lang.Long> arc
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fstReader
private final FST.BytesReader fstReader
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wordIdRef
private final IntsRef wordIdRef
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userFSTReader
private final FST.BytesReader userFSTReader
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userFST
private final TokenInfoFST userFST
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discardPunctuation
private final boolean discardPunctuation
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mode
private final KoreanTokenizer.DecompoundMode mode
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outputUnknownUnigrams
private final boolean outputUnknownUnigrams
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buffer
private final RollingCharBuffer buffer
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positions
private final KoreanTokenizer.WrappedPositionArray positions
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end
private boolean end
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lastBackTracePos
private int lastBackTracePos
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pos
private int pos
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pending
private final java.util.List<Token> pending
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termAtt
private final CharTermAttribute termAtt
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offsetAtt
private final OffsetAttribute offsetAtt
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posIncAtt
private final PositionIncrementAttribute posIncAtt
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posLengthAtt
private final PositionLengthAttribute posLengthAtt
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posAtt
private final PartOfSpeechAttribute posAtt
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readingAtt
private final ReadingAttribute readingAtt
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dotOut
private GraphvizFormatter dotOut
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Constructor Detail
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KoreanTokenizer
public KoreanTokenizer()
Creates a new KoreanTokenizer with default parameters.Uses the default AttributeFactory.
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KoreanTokenizer
public KoreanTokenizer(AttributeFactory factory, UserDictionary userDictionary, KoreanTokenizer.DecompoundMode mode, boolean outputUnknownUnigrams)
Create a new KoreanTokenizer using the system and unknown dictionaries shipped with Lucene.- Parameters:
factory
- the AttributeFactory to useuserDictionary
- Optional: if non-null, user dictionary.mode
- Decompound mode.outputUnknownUnigrams
- if true outputs unigrams for unknown words.
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KoreanTokenizer
public KoreanTokenizer(AttributeFactory factory, UserDictionary userDictionary, KoreanTokenizer.DecompoundMode mode, boolean outputUnknownUnigrams, boolean discardPunctuation)
Create a new KoreanTokenizer using the system and unknown dictionaries shipped with Lucene.- Parameters:
factory
- the AttributeFactory to useuserDictionary
- Optional: if non-null, user dictionary.mode
- Decompound mode.outputUnknownUnigrams
- if true outputs unigrams for unknown words.discardPunctuation
- true if punctuation tokens should be dropped from the output.
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KoreanTokenizer
public KoreanTokenizer(AttributeFactory factory, TokenInfoDictionary systemDictionary, UnknownDictionary unkDictionary, ConnectionCosts connectionCosts, UserDictionary userDictionary, KoreanTokenizer.DecompoundMode mode, boolean outputUnknownUnigrams, boolean discardPunctuation)
Create a new KoreanTokenizer supplying a custom system dictionary and unknown dictionary. This constructor provides an entry point for users that want to construct custom language models that can be used as input toDictionaryBuilder
.- Parameters:
factory
- the AttributeFactory to usesystemDictionary
- a custom known token dictionaryunkDictionary
- a custom unknown token dictionaryconnectionCosts
- custom token transition costsuserDictionary
- Optional: if non-null, user dictionary.mode
- Decompound mode.outputUnknownUnigrams
- if true outputs unigrams for unknown words.discardPunctuation
- true if punctuation tokens should be dropped from the output.
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Method Detail
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setGraphvizFormatter
public void setGraphvizFormatter(GraphvizFormatter dotOut)
Expert: set this to produce graphviz (dot) output of the Viterbi lattice
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close
public void close() throws java.io.IOException
Description copied from class:Tokenizer
Releases resources associated with this stream.If you override this method, always call
super.close()
, otherwise some internal state will not be correctly reset (e.g.,Tokenizer
will throwIllegalStateException
on reuse).NOTE: The default implementation closes the input Reader, so be sure to call
super.close()
when overriding this method.
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reset
public void reset() throws java.io.IOException
Description copied from class:TokenStream
This method is called by a consumer before it begins consumption usingTokenStream.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 throwIllegalStateException
on further usage).
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resetState
private void resetState()
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end
public void end() throws java.io.IOException
Description copied from class:TokenStream
This method is called by the consumer after the last token has been consumed, afterTokenStream.incrementToken()
returnedfalse
(using the newTokenStream
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()
.- Overrides:
end
in classTokenStream
- Throws:
java.io.IOException
- If an I/O error occurs
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computeSpacePenalty
private int computeSpacePenalty(POS.Tag leftPOS, int numSpaces)
Returns the space penalty associated with the providedPOS.Tag
.- Parameters:
leftPOS
- the left part of speech of the current token.numSpaces
- the number of spaces before the current token.
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add
private void add(Dictionary dict, KoreanTokenizer.Position fromPosData, int wordPos, int endPos, int wordID, KoreanTokenizer.Type type)
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incrementToken
public boolean incrementToken() throws java.io.IOException
Description copied from class:TokenStream
Consumers (i.e.,IndexWriter
) use this method to advance the stream to the next token. Implementing classes must implement this method and update the appropriateAttributeImpl
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)
andAttributeSource.getAttribute(Class)
, references to allAttributeImpl
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()
.- Specified by:
incrementToken
in classTokenStream
- Returns:
- false for end of stream; true otherwise
- Throws:
java.io.IOException
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parse
private void parse() throws java.io.IOException
- Throws:
java.io.IOException
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backtrace
private void backtrace(KoreanTokenizer.Position endPosData, int fromIDX)
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getDict
Dictionary getDict(KoreanTokenizer.Type type)
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shouldFilterToken
private boolean shouldFilterToken(Token token)
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isPunctuation
private static boolean isPunctuation(char ch)
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isPunctuation
private static boolean isPunctuation(char ch, int cid)
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isCommonOrInherited
private static boolean isCommonOrInherited(java.lang.Character.UnicodeScript script)
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isSameScript
private static boolean isSameScript(java.lang.Character.UnicodeScript scriptOne, java.lang.Character.UnicodeScript scriptTwo)
Determine if two scripts are compatible.
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