Class AnalyzingQueryParser

  • All Implemented Interfaces:
    QueryParserConstants

    public class AnalyzingQueryParser
    extends QueryParser
    Overrides Lucene's default QueryParser so that Fuzzy-, Prefix-, Range-, and WildcardQuerys are also passed through the given analyzer, but wild card characters (like *) don't get removed from the search terms.

    Warning: This class should only be used with analyzers that do not use stopwords or that add tokens. Also, several stemming analyzers are inappropriate: for example, GermanAnalyzer will turn Häuser into hau, but H?user will become h?user when using this parser and thus no match would be found (i.e. using this parser will be no improvement over QueryParser in such cases).

    Version:
    $Revision$, $Date$
    • Constructor Detail

      • AnalyzingQueryParser

        public AnalyzingQueryParser​(Version matchVersion,
                                    String field,
                                    Analyzer analyzer)
        Constructs a query parser.
        Parameters:
        field - the default field for query terms.
        analyzer - used to find terms in the query text.
    • Method Detail

      • getWildcardQuery

        protected Query getWildcardQuery​(String field,
                                         String termStr)
                                  throws ParseException
        Called when parser parses an input term token that contains one or more wildcard characters (like *), but is not a prefix term token (one that has just a single * character at the end).

        Example: will be called for H?user or for H*user but not for *user.

        Depending on analyzer and settings, a wildcard term may (most probably will) be lower-cased automatically. It will go through the default Analyzer.

        Overrides super class, by passing terms through analyzer.

        Overrides:
        getWildcardQuery in class QueryParser
        Parameters:
        field - Name of the field query will use.
        termStr - Term token that contains one or more wild card characters (? or *), but is not simple prefix term
        Returns:
        Resulting Query built for the term
        Throws:
        ParseException
      • getPrefixQuery

        protected Query getPrefixQuery​(String field,
                                       String termStr)
                                throws ParseException
        Called when parser parses an input term token that uses prefix notation; that is, contains a single '*' wildcard character as its last character. Since this is a special case of generic wildcard term, and such a query can be optimized easily, this usually results in a different query object.

        Depending on analyzer and settings, a prefix term may (most probably will) be lower-cased automatically. It will go through the default Analyzer.

        Overrides super class, by passing terms through analyzer.

        Overrides:
        getPrefixQuery in class QueryParser
        Parameters:
        field - Name of the field query will use.
        termStr - Term token to use for building term for the query (without trailing '*' character!)
        Returns:
        Resulting Query built for the term
        Throws:
        ParseException
      • getFuzzyQuery

        protected Query getFuzzyQuery​(String field,
                                      String termStr,
                                      float minSimilarity)
                               throws ParseException
        Called when parser parses an input term token that has the fuzzy suffix (~) appended.

        Depending on analyzer and settings, a fuzzy term may (most probably will) be lower-cased automatically. It will go through the default Analyzer.

        Overrides super class, by passing terms through analyzer.

        Overrides:
        getFuzzyQuery in class QueryParser
        Parameters:
        field - Name of the field query will use.
        termStr - Term token to use for building term for the query
        Returns:
        Resulting Query built for the term
        Throws:
        ParseException