Package org.apache.lucene.analysis.compound

Class CompoundWordTokenFilterBase

java.lang.Object
org.apache.lucene.util.AttributeSource
org.apache.lucene.analysis.TokenStream
org.apache.lucene.analysis.TokenFilter
org.apache.lucene.analysis.compound.CompoundWordTokenFilterBase
All Implemented Interfaces:
Closeable, AutoCloseable
Direct Known Subclasses:
DictionaryCompoundWordTokenFilter, HyphenationCompoundWordTokenFilter
public abstract class CompoundWordTokenFilterBase extends TokenFilter
Base class for decomposition token filters.

You must specify the required Version compatibility when creating CompoundWordTokenFilterBase:

  • As of 3.1, CompoundWordTokenFilterBase correctly handles Unicode 4.0 supplementary characters in strings and char arrays provided as compound word dictionaries.
  • As of 4.4, CompoundWordTokenFilterBase doesn't update offsets.

  • Field Details

    • DEFAULT_MIN_WORD_SIZE

      public static final int DEFAULT_MIN_WORD_SIZE
      The default for minimal word length that gets decomposed
      See Also:

    • DEFAULT_MIN_SUBWORD_SIZE

      public static final int DEFAULT_MIN_SUBWORD_SIZE
      The default for minimal length of subwords that get propagated to the output of this filter
      See Also:

    • DEFAULT_MAX_SUBWORD_SIZE

      public static final int DEFAULT_MAX_SUBWORD_SIZE
      The default for maximal length of subwords that get propagated to the output of this filter
      See Also:

  • Method Details

    • incrementToken

      public final 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 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:
      IOException

    • reset

      public void reset() throws IOException
      Description copied from class: TokenFilter
      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).

      NOTE: The default implementation chains the call to the input TokenStream, so be sure to call super.reset() when overriding this method.

      Overrides:
      reset in class TokenFilter
      Throws:
      IOException