Package org.terrier.matching.dsms

Class BooleanFallback

  • All Implemented Interfaces:
    java.lang.Cloneable, DocumentScoreModifier
    public class BooleanFallback
extends java.lang.Object
implements DocumentScoreModifier
    This class provides a boolean fallback document score modifier for matching. In other words, if there any of the retrieved documents contain all undecorated query terms (ie query terms without any operators), then we remove from the result set documents that do not contain all undecorated query terms. Otherwise, we do nothing.
    Author:
    Vassilis Plachouras & Craig Macdonald

    • Field Summary

      Fields 
      Modifier and Type Field Description
      protected static org.slf4j.Logger logger  

    • Constructor Summary

      Constructors 
      Constructor Description
      BooleanFallback()  

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      java.lang.Object clone()
      Creates the close of this object
      protected java.util.HashSet<java.lang.String> getMinusTerms​(Query q)
      Builds a hashset containing all terms that are required NOT to be in the query
      java.lang.String getName()
      Returns the name of the modifier, which is BooleanFallback.
      boolean modifyScores​(Index index, MatchingQueryTerms queryTerms, ResultSet resultSet)
      Applies boolean fallback to the given result set.

      • Methods inherited from class java.lang.Object

        equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Field Detail

      • logger

        protected static final org.slf4j.Logger logger

    • Constructor Detail

      • BooleanFallback

        public BooleanFallback()

    • Method Detail

      • getMinusTerms

        protected java.util.HashSet<java.lang.String> getMinusTerms​(Query q)
        Builds a hashset containing all terms that are required NOT to be in the query
        Parameters:
        q - The original query as was used to generate MatchingQueryTerms
        Returns:
        See above

      • modifyScores

        public boolean modifyScores​(Index index,
                            MatchingQueryTerms queryTerms,
                            ResultSet resultSet)
        Applies boolean fallback to the given result set.
        Specified by:
        modifyScores in interface DocumentScoreModifier
        Parameters:
        index - The data structures used for retrieval.
        queryTerms - the terms of the query.
        resultSet - the set of retrieved documents for the query.
        Returns:
        true if any scores have been altered

      • getName

        public java.lang.String getName()
        Returns the name of the modifier, which is BooleanFallback.
        Specified by:
        getName in interface DocumentScoreModifier
        Returns:
        the name of the modifier.

      • clone

        public java.lang.Object clone()
        Creates the close of this object
        Specified by:
        clone in interface DocumentScoreModifier
        Overrides:
        clone in class java.lang.Object