Class TypeAsSynonymFilter

All Implemented Interfaces:
Closeable, AutoCloseable, Unwrappable<TokenStream>

public final class TypeAsSynonymFilter extends TokenFilter
Adds the TypeAttribute.type() as a synonym, i.e. another token at the same position, optionally with a specified prefix prepended, optionally transfering flags, and optionally ignoring some types. See TypeAsSynonymFilterFactory for full details.
  • Field Details

  • Constructor Details

    • TypeAsSynonymFilter

      public TypeAsSynonymFilter(TokenStream input)
    • TypeAsSynonymFilter

      public TypeAsSynonymFilter(TokenStream input, String prefix)
      Parameters:
      input - input tokenstream
      prefix - Prepend this string to every token type emitted as token text. If null, nothing will be prepended.
    • TypeAsSynonymFilter

      public TypeAsSynonymFilter(TokenStream input, String prefix, Set<String> ignore, int synFlagsMask)
      Parameters:
      input - input tokenstream
      prefix - Prepend this string to every token type emitted as token text. If null, nothing will be prepended.
      ignore - types to ignore (and not convert to a synonym)
      synFlagsMask - a mask to control what flags are propagated to the synonym.
  • Method Details

    • 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 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