Class StemmerOverrideFilter

  • All Implemented Interfaces:, java.lang.AutoCloseable

    public final class StemmerOverrideFilter
    extends TokenFilter
    Provides the ability to override any KeywordAttribute aware stemmer with custom dictionary-based stemming.
    • Constructor Detail

      • StemmerOverrideFilter

        public StemmerOverrideFilter​(TokenStream input,
                                     StemmerOverrideFilter.StemmerOverrideMap stemmerOverrideMap)
        Create a new StemmerOverrideFilter, performing dictionary-based stemming with the provided dictionary.

        Any dictionary-stemmed terms will be marked with KeywordAttribute so that they will not be stemmed with stemmers down the chain.

    • Method Detail

      • incrementToken

        public boolean incrementToken()
        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
        false for end of stream; true otherwise