Package org.apache.lucene.analysis.cn

Class ChineseTokenizer

  • All Implemented Interfaces:
    java.io.Closeable, java.lang.AutoCloseable
    @Deprecated
public final class ChineseTokenizer
extends Tokenizer
    Deprecated.
    (3.1) Use StandardTokenizer instead, which has the same functionality. This filter will be removed in Lucene 5.0
    Tokenize Chinese text as individual chinese characters.

    The difference between ChineseTokenizer and CJKTokenizer is that they have different token parsing logic.

    For example, if the Chinese text "C1C2C3C4" is to be indexed:

    • The tokens returned from ChineseTokenizer are C1, C2, C3, C4.
    • The tokens returned from the CJKTokenizer are C1C2, C2C3, C3C4.

    Therefore the index created by CJKTokenizer is much larger.

    The problem is that when searching for C1, C1C2, C1C3, C4C2, C1C2C3 ... the ChineseTokenizer works, but the CJKTokenizer will not work.

    • Constructor Detail

      • ChineseTokenizer

        public ChineseTokenizer​(java.io.Reader in)
        Deprecated.

    • Method Detail

      • incrementToken

        public boolean incrementToken()
                       throws java.io.IOException
        Deprecated.
        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 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 AttributeSource.addAttribute(Class) and AttributeSource.getAttribute(Class), 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 TokenStream.incrementToken().

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

      • end

        public final void end()
               throws java.io.IOException
        Deprecated.
        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.

        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 class TokenStream
        Throws:
        java.io.IOException - If an I/O error occurs

      • reset

        public void reset()
           throws java.io.IOException
        Deprecated.
        Description copied from class: TokenStream
        This method is called by a consumer before it begins consumption using 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).

        Overrides:
        reset in class Tokenizer
        Throws:
        java.io.IOException