Package com.yahoo.prelude.querytransform

Class PhraseMatcher

java.lang.Object
com.yahoo.prelude.querytransform.PhraseMatcher
public class PhraseMatcher extends Object
Detects query phrases using an automaton. This class is thread safe.
Author:
bratseth

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Class
    Description
    static class 
    PhraseMatcher.Phrase
    Points to a collection of word items (one or more) which is matches a complete listing in an automat

  • Constructor Summary

    Constructors
    Constructor
    Description
    PhraseMatcher(com.yahoo.fsa.FSA phraseAutomatonFSA, boolean ignorePluralForm)
    Creates a phrase matcher
    PhraseMatcher(String phraseAutomatonFile)
    Creates a phrase matcher.
    PhraseMatcher(String phraseAutomatonFile, boolean ignorePluralForm)
    Creates a phrase matcher

  • Method Summary

    Modifier and Type
    Method
    Description
    static PhraseMatcher
    getNullMatcher()
    Returns a phrase matcher which (quickly) never matches anything
    boolean
    isEmpty()
     
    List<PhraseMatcher.Phrase>
    matchPhrases(Item queryItem)
    Finds all phrases (word sequences of length 1 or higher) of the same index, not negative items of a notitem, which constitutes a complete entry in the automaton of this matcher
    void
    setIgnorePluralForm(boolean ignorePluralForm)
    Sets whether we should ignore plural/singular form when matching
    void
    setMatchAll(boolean matchAll)
    Sets whether to return the longest matching phrase when there are overlapping matches (default), or all matching phrases
    void
    setMatchPhraseItems(boolean matchPhraseItems)
    Set whether to match words contained in phrase items as well.
    void
    setMatchSingleItems(boolean matchSingleItems)
    Sets whether single items should be matched and returned as phrase matches.

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • PhraseMatcher

      public PhraseMatcher(String phraseAutomatonFile)
      Creates a phrase matcher. This will not ignore plural/singular form differences when matching
      Parameters:
      phraseAutomatonFile - the file containing phrases to match
      Throws:
      IllegalArgumentException - if the file is not found

    • PhraseMatcher

      public PhraseMatcher(String phraseAutomatonFile, boolean ignorePluralForm)
      Creates a phrase matcher
      Parameters:
      phraseAutomatonFile - the file containing phrases to match
      ignorePluralForm - whether we should ignore plural and singular forms as matches
      Throws:
      IllegalArgumentException - if the file is not found

    • PhraseMatcher

      public PhraseMatcher(com.yahoo.fsa.FSA phraseAutomatonFSA, boolean ignorePluralForm)
      Creates a phrase matcher
      Parameters:
      phraseAutomatonFSA - the fsa containing phrases to match
      ignorePluralForm - whether we should ignore plural and singular forms as matches
      Throws:
      IllegalArgumentException - if FSA is null

  • Method Details

    • isEmpty

      public boolean isEmpty()

    • setMatchPhraseItems

      public void setMatchPhraseItems(boolean matchPhraseItems)
      Set whether to match words contained in phrase items as well. Default is false - don't match words contained in phrase items

    • setMatchSingleItems

      public void setMatchSingleItems(boolean matchSingleItems)
      Sets whether single items should be matched and returned as phrase matches. Default is false.

    • setIgnorePluralForm

      public void setIgnorePluralForm(boolean ignorePluralForm)
      Sets whether we should ignore plural/singular form when matching

    • setMatchAll

      public void setMatchAll(boolean matchAll)
      Sets whether to return the longest matching phrase when there are overlapping matches (default), or all matching phrases

    • matchPhrases

      public List<PhraseMatcher.Phrase> matchPhrases(Item queryItem)
      Finds all phrases (word sequences of length 1 or higher) of the same index, not negative items of a notitem, which constitutes a complete entry in the automaton of this matcher
      Parameters:
      queryItem - the root query item in which to match phrases
      Returns:
      the matched phrases, or null if there was no matches

    • getNullMatcher

      public static PhraseMatcher getNullMatcher()
      Returns a phrase matcher which (quickly) never matches anything