Class PatternTypingFilter

  • All Implemented Interfaces:
    java.io.Closeable, java.lang.AutoCloseable, Unwrappable<TokenStream>

    public class PatternTypingFilter
    extends TokenFilter
    Set a type attribute to a parameterized value when tokens are matched by any of a several regex patterns. The value set in the type attribute is parameterized with the match groups of the regex used for matching. In combination with TypeAsSynonymFilter and DropIfFlagged filter this can supply complex synonym patterns that are protected from subsequent analysis, and optionally drop the original term based on the flag set in this filter. See PatternTypingFilterFactory for full documentation.
    Since:
    8.8.0
    See Also:
    PatternTypingFilterFactory
    • Method Detail

      • incrementToken

        public final boolean incrementToken()
                                     throws java.io.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:
        java.io.IOException