ICUTokenizer (Lucene 3.6.2 API)
Keywords: org.apache.lucene.analysis.icu.segmentation.ICUTokenizer class

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## org.apache.lucene.analysis.icu.segmentation
Class ICUTokenizer

    java.lang.Object
      org.apache.lucene.util.AttributeSource
          org.apache.lucene.analysis.TokenStream
              org.apache.lucene.analysis.Tokenizer
                  org.apache.lucene.analysis.icu.segmentation.ICUTokenizer

All Implemented Interfaces:
  Closeable

    public final class ICUTokenizer

extends Tokenizer

Breaks text into words according to UAX #29: Unicode Text Segmentation (http://www.unicode.org/reports/tr29/)

Words are broken across script boundaries, then segmented according to the BreakIterator and typing provided by the `ICUTokenizerConfig`

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

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource
`AttributeSource.AttributeFactory, AttributeSource.State`

Field Summary

Fields inherited from class org.apache.lucene.analysis.Tokenizer
`input`

Constructor Summary
`ICUTokenizer(Reader input)` Construct a new ICUTokenizer that breaks text into words from the given Reader.
`ICUTokenizer(Reader input, ICUTokenizerConfig config)` Construct a new ICUTokenizer that breaks text into words from the given Reader, using a tailored BreakIterator configuration.

Method Summary
`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).
`boolean` | `incrementToken()` Consumers (i.e., `IndexWriter`) use this method to advance the stream to the next token.
`void` | `reset()` Resets this stream to the beginning.
`void` | `reset(Reader input)` Expert: Reset the tokenizer to a new reader.

Methods inherited from class org.apache.lucene.analysis.Tokenizer
`close, correctOffset`

Methods inherited from class org.apache.lucene.util.AttributeSource
`addAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, copyTo, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, reflectAsString, reflectWith, restoreState, toString`

Methods inherited from class java.lang.Object
`clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

Constructor Detail

### ICUTokenizer

    public ICUTokenizer(Reader input)

  Construct a new ICUTokenizer that breaks text into words from the given Reader.

  The default script-specific handling is used.

  Parameters:
    `input` - Reader containing text to tokenize.
  See Also:
    `DefaultICUTokenizerConfig`

### ICUTokenizer

    public ICUTokenizer(Reader input,
                        ICUTokenizerConfig config)

  Construct a new ICUTokenizer that breaks text into words from the given Reader, using a tailored BreakIterator configuration.

  Parameters:
    `input` - Reader containing text to tokenize.
    `config` - Tailored BreakIterator configuration

Method Detail

### incrementToken

    public boolean incrementToken()
                           throws 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 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()`.

  Specified by:
    `incrementToken` in class `TokenStream`
  Returns:
    false for end of stream; true otherwise
  Throws:
    `IOException`

### reset

    public void reset()
               throws IOException

  Description copied from class: `TokenStream`
  Resets this stream to the beginning. This is an optional operation, so subclasses may or may not implement this method. `TokenStream.reset()` is not needed for the standard indexing process. However, if the tokens of a `TokenStream` are 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 `TokenStream.reset()`).

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

### reset

    public void reset(Reader input)
               throws IOException

  Description copied from class: `Tokenizer`
  Expert: Reset the tokenizer to a new reader. Typically, an analyzer (in its reusableTokenStream method) will use this to re-use a previously created tokenizer.

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

### end

    public void end()
             throws IOException

  Description copied from class: `TokenStream`
  This method is called by the consumer after the last token has been consumed, after `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.

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

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