Package org.apache.lucene.search.highlight

Class QueryScorer

java.lang.Object
org.apache.lucene.search.highlight.QueryScorer
All Implemented Interfaces:
Scorer
public class QueryScorer extends Object implements Scorer
Scorer implementation which scores text fragments by the number of unique query terms found. This class converts appropriate Querys to SpanQuerys and attempts to score only those terms that participated in generating the 'hit' on the document.

  • Constructor Details

    • QueryScorer

      public QueryScorer(Query query)
      Parameters:
      query - Query to use for highlighting

    • QueryScorer

      public QueryScorer(Query query, String field)
      Parameters:
      query - Query to use for highlighting
      field - Field to highlight - pass null to ignore fields

    • QueryScorer

      public QueryScorer(Query query, IndexReader reader, String field)
      Parameters:
      query - Query to use for highlighting
      field - Field to highlight - pass null to ignore fields
      reader - IndexReader to use for quasi tf/idf scoring

    • QueryScorer

      public QueryScorer(Query query, IndexReader reader, String field, String defaultField)
      Parameters:
      query - to use for highlighting
      reader - IndexReader to use for quasi tf/idf scoring
      field - to highlight - pass null to ignore fields

    • QueryScorer

      public QueryScorer(Query query, String field, String defaultField)
      Parameters:
      defaultField - - The default field for queries with the field name unspecified

    • QueryScorer

      public QueryScorer(WeightedSpanTerm[] weightedTerms)
      Parameters:
      weightedTerms - an array of pre-created WeightedSpanTerms

  • Method Details

    • getFragmentScore

      public float getFragmentScore()
      Description copied from interface: Scorer
      Called when the Highlighter has no more tokens for the current fragment - the Scorer returns the weighting it has derived for the most recent fragment, typically based on the results of Scorer.getTokenScore().
      Specified by:
      getFragmentScore in interface Scorer

    • getMaxTermWeight

      public float getMaxTermWeight()
      Returns:
      The highest weighted term (useful for passing to GradientFormatter to set top end of coloring scale).

    • getTokenScore

      public float getTokenScore()
      Description copied from interface: Scorer
      Called for each token in the current fragment. The Highlighter will increment the TokenStream passed to init on every call.
      Specified by:
      getTokenScore in interface Scorer
      Returns:
      a score which is passed to the Highlighter class to influence the mark-up of the text (this return value is NOT used to score the fragment)

    • init

      public TokenStream init(TokenStream tokenStream) throws IOException
      Description copied from interface: Scorer
      Called to init the Scorer with a TokenStream. You can grab references to the attributes you are interested in here and access them from Scorer.getTokenScore().
      Specified by:
      init in interface Scorer
      Parameters:
      tokenStream - the TokenStream that will be scored.
      Returns:
      either a TokenStream that the Highlighter should continue using (eg if you read the tokenSream in this method) or null to continue using the same TokenStream that was passed in.
      Throws:
      IOException - If there is a low-level I/O error

    • getWeightedSpanTerm

      public WeightedSpanTerm getWeightedSpanTerm(String token)
      Retrieve the WeightedSpanTerm for the specified token. Useful for passing Span information to a Fragmenter.
      Parameters:
      token - to get WeightedSpanTerm for
      Returns:
      WeightedSpanTerm for token

    • newTermExtractor

      protected WeightedSpanTermExtractor newTermExtractor(String defaultField)

    • startFragment

      public void startFragment(TextFragment newFragment)
      Description copied from interface: Scorer
      Called when a new fragment is started for consideration.
      Specified by:
      startFragment in interface Scorer
      Parameters:
      newFragment - the fragment that will be scored next

    • isExpandMultiTermQuery

      public boolean isExpandMultiTermQuery()
      Returns:
      true if multi-term queries should be expanded

    • setExpandMultiTermQuery

      public void setExpandMultiTermQuery(boolean expandMultiTermQuery)
      Controls whether or not multi-term queries are expanded against a MemoryIndex IndexReader.
      Parameters:
      expandMultiTermQuery - true if multi-term queries should be expanded

    • isUsePayloads

      public boolean isUsePayloads()
      Whether or not we should capture payloads in MemoryIndex at each position so that queries can access them. This does not apply to term vector based TokenStreams, which support payloads only when the term vector has them.

    • setUsePayloads

      public void setUsePayloads(boolean usePayloads)

    • setWrapIfNotCachingTokenFilter

      public void setWrapIfNotCachingTokenFilter(boolean wrap)
      By default, TokenStreams that are not of the type CachingTokenFilter are wrapped in a CachingTokenFilter to ensure an efficient reset - if you are already using a different caching TokenStream impl and you don't want it to be wrapped, set this to false. Note that term-vector based tokenstreams are detected and won't be wrapped either.

    • setMaxDocCharsToAnalyze

      public void setMaxDocCharsToAnalyze(int maxDocCharsToAnalyze)