org.apache.lucene.analysis.ko

## Class KoreanTokenizer

- java.lang.Object
- - org.apache.lucene.util.AttributeSource
  - - org.apache.lucene.analysis.TokenStream
    - - org.apache.lucene.analysis.Tokenizer
      - - org.apache.lucene.analysis.ko.KoreanTokenizer

- All Implemented Interfaces:
    Closeable, 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.

  WARNING: This API is experimental and might change in incompatible ways in the next release.

- - ### Nested Class Summary

    Nested Classes
    Modifier and Type | Class and Description
    --- | ---
    `static class` | `KoreanTokenizer.DecompoundMode` Decompound mode: this determines how the tokenizer handles `POS.Type.COMPOUND`, `POS.Type.INFLECT` and `POS.Type.PREANALYSIS` tokens.
    `static class` | `KoreanTokenizer.Type` Token type reflecting the original source of this token

    - ### Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource

      `AttributeSource.State`

  - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static KoreanTokenizer.DecompoundMode` | `DEFAULT_DECOMPOUND` Default mode for the decompound of tokens (`KoreanTokenizer.DecompoundMode.DISCARD`.

    - ### Fields inherited from class org.apache.lucene.analysis.Tokenizer

      `input`

    - ### Fields inherited from class org.apache.lucene.analysis.TokenStream

      `DEFAULT_TOKEN_ATTRIBUTE_FACTORY`

  - ### Constructor Summary

    Constructors
    Constructor and 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.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `close()`
    `void` | `end()`
    `boolean` | `incrementToken()`
    `void` | `reset()`
    `void` | `setGraphvizFormatter(GraphvizFormatter dotOut)` Expert: set this to produce graphviz (dot) output of the Viterbi lattice

    - ### Methods inherited from class org.apache.lucene.analysis.Tokenizer

      `correctOffset, setReader`

    - ### 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`

    - ### Methods inherited from class java.lang.Object

      `clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

- - ### Field Detail

    - #### DEFAULT_DECOMPOUND

          public static final KoreanTokenizer.DecompoundMode DEFAULT_DECOMPOUND

      Default mode for the decompound of tokens (`KoreanTokenizer.DecompoundMode.DISCARD`.

  - ### Constructor Detail

    - #### KoreanTokenizer

          public KoreanTokenizer()

      Creates a new KoreanTokenizer with default parameters.

      Uses the default AttributeFactory.

    - #### 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 use
        `userDictionary` - Optional: if non-null, user dictionary.
        `mode` - Decompound mode.
        `outputUnknownUnigrams` - if true outputs unigrams for unknown words.

    - #### 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 use
        `userDictionary` - 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.

    - #### 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 to `DictionaryBuilder`.

      Parameters:
        `factory` - the AttributeFactory to use
        `systemDictionary` - a custom known token dictionary
        `unkDictionary` - a custom unknown token dictionary
        `connectionCosts` - custom token transition costs
        `userDictionary` - 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.
      WARNING: This API is experimental and might change in incompatible ways in the next release.

  - ### Method Detail

    - #### setGraphvizFormatter

          public void setGraphvizFormatter(GraphvizFormatter dotOut)

      Expert: set this to produce graphviz (dot) output of the Viterbi lattice

    - #### close

          public void close()
                     throws IOException

      Specified by:
        `close` in interface `Closeable`
      Specified by:
        `close` in interface `AutoCloseable`
      Overrides:
        `close` in class `Tokenizer`
      Throws:
        `IOException`

    - #### reset

          public void reset()
                     throws IOException

      Overrides:
        `reset` in class `Tokenizer`
      Throws:
        `IOException`

    - #### end

          public void end()
                   throws IOException

      Overrides:
        `end` in class `TokenStream`
      Throws:
        `IOException`

    - #### incrementToken

          public boolean incrementToken()
                                 throws IOException

      Specified by:
        `incrementToken` in class `TokenStream`
      Throws:
        `IOException`

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