Module org.apache.lucene.highlighter
Package org.apache.lucene.search.uhighlight

Class AnalysisOffsetStrategy.MultiValueTokenStream

java.lang.Object
org.apache.lucene.util.AttributeSource
org.apache.lucene.analysis.TokenStream
org.apache.lucene.analysis.TokenFilter
org.apache.lucene.search.uhighlight.AnalysisOffsetStrategy.MultiValueTokenStream
All Implemented Interfaces:
Closeable, AutoCloseable, Unwrappable<TokenStream>
Enclosing class:
AnalysisOffsetStrategy
private static final class AnalysisOffsetStrategy.MultiValueTokenStream extends TokenFilter
Wraps an Analyzer and string text that represents multiple values delimited by a specified character. This exposes a TokenStream that matches what would get indexed considering the Analyzer.getPositionIncrementGap(String). Currently this assumes Analyzer.getOffsetGap(String) is 1; an exception will be thrown if it isn't.

It would be more orthogonal for this to be an Analyzer since we're wrapping an Analyzer but doing so seems like more work. The underlying components see a Reader not a String -- and the String is easy to split up without redundant buffering.

  • Field Details

    • fieldName

      private final String fieldName

    • indexAnalyzer

      private final Analyzer indexAnalyzer

    • content

      private final String content

    • splitChar

      private final char splitChar

    • posIncAtt

      private final PositionIncrementAttribute posIncAtt

    • offsetAtt

      private final OffsetAttribute offsetAtt

    • startValIdx

      private int startValIdx

    • endValIdx

      private int endValIdx

    • remainingPosInc

      private int remainingPosInc

  • Constructor Details

    • MultiValueTokenStream

      private MultiValueTokenStream(TokenStream subTokenStream, String fieldName, Analyzer indexAnalyzer, String content, char splitChar, int splitCharIdx)

  • Method Details

    • 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

    • 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

    • end

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

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

      Overrides:
      end in class TokenFilter
      Throws:
      IOException - If an I/O error occurs