Package org.apache.lucene.queryParser

Class MultiFieldQueryParser

  • All Implemented Interfaces:
    QueryParserConstants
    public class MultiFieldQueryParser
extends QueryParser
    A QueryParser which constructs queries to search multiple fields.
    Version:
    $Revision$

    • Constructor Detail

      • MultiFieldQueryParser

        public MultiFieldQueryParser​(Version matchVersion,
                             String[] fields,
                             Analyzer analyzer,
                             Map<String,​Float> boosts)
        Creates a MultiFieldQueryParser. Allows passing of a map with term to Boost, and the boost to apply to each term.

        It will, when parse(String query) is called, construct a query like this (assuming the query consists of two terms and you specify the two fields title and body):

        (title:term1 body:term1) (title:term2 body:term2)

        When setDefaultOperator(AND_OPERATOR) is set, the result will be:

        +(title:term1 body:term1) +(title:term2 body:term2)

        When you pass a boost (title=>5 body=>10) you can get

        +(title:term1^5.0 body:term1^10.0) +(title:term2^5.0 body:term2^10.0)

        In other words, all the query's terms must appear, but it doesn't matter in what fields they appear.

      • MultiFieldQueryParser

        public MultiFieldQueryParser​(Version matchVersion,
                             String[] fields,
                             Analyzer analyzer)
        Creates a MultiFieldQueryParser.

        It will, when parse(String query) is called, construct a query like this (assuming the query consists of two terms and you specify the two fields title and body):

        (title:term1 body:term1) (title:term2 body:term2)

        When setDefaultOperator(AND_OPERATOR) is set, the result will be:

        +(title:term1 body:term1) +(title:term2 body:term2)

        In other words, all the query's terms must appear, but it doesn't matter in what fields they appear.

    • Method Detail

      • getPrefixQuery

        protected Query getPrefixQuery​(String field,
                               String termStr)
                        throws ParseException
        Description copied from class: QueryParser
        Factory method for generating a query (similar to QueryParser.getWildcardQuery(java.lang.String, java.lang.String)). 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 settings, a prefix term may be lower-cased automatically. It will not go through the default Analyzer, however, since normal Analyzers are unlikely to work properly with wildcard templates.

        Can be overridden by extending classes, to provide custom handling for wild card queries, which may be necessary due to missing analyzer calls.

        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 - throw in overridden method to disallow

      • getWildcardQuery

        protected Query getWildcardQuery​(String field,
                                 String termStr)
                          throws ParseException
        Description copied from class: QueryParser
        Factory method for generating a query. Called when parser parses an input term token that contains one or more wildcard characters (? and *), but is not a prefix term token (one that has just a single * character at the end)

        Depending on settings, prefix term may be lower-cased automatically. It will not go through the default Analyzer, however, since normal Analyzers are unlikely to work properly with wildcard templates.

        Can be overridden by extending classes, to provide custom handling for wildcard queries, which may be necessary due to missing analyzer calls.

        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 - throw in overridden method to disallow

      • parse

        public static Query parse​(Version matchVersion,
                          String[] queries,
                          String[] fields,
                          Analyzer analyzer)
                   throws ParseException
        Parses a query which searches on the fields specified.

        If x fields are specified, this effectively constructs: 

         
 (field1:query1) (field2:query2) (field3:query3)...(fieldx:queryx)
        Parameters:
        matchVersion - Lucene version to match; this is passed through to QueryParser.
        queries - Queries strings to parse
        fields - Fields to search on
        analyzer - Analyzer to use
        Throws:
        ParseException - if query parsing fails
        IllegalArgumentException - if the length of the queries array differs from the length of the fields array

      • parse

        public static Query parse​(Version matchVersion,
                          String query,
                          String[] fields,
                          BooleanClause.Occur[] flags,
                          Analyzer analyzer)
                   throws ParseException
        Parses a query, searching on the fields specified. Use this if you need to specify certain fields as required, and others as prohibited. 

         Usage:
 
 String[] fields = {"filename", "contents", "description"};
 BooleanClause.Occur[] flags = {BooleanClause.Occur.SHOULD,
                BooleanClause.Occur.MUST,
                BooleanClause.Occur.MUST_NOT};
 MultiFieldQueryParser.parse("query", fields, flags, analyzer);

        The code above would construct a query: 

         
 (filename:query) +(contents:query) -(description:query)
        Parameters:
        matchVersion - Lucene version to match; this is passed through to QueryParser.
        query - Query string to parse
        fields - Fields to search on
        flags - Flags describing the fields
        analyzer - Analyzer to use
        Throws:
        ParseException - if query parsing fails
        IllegalArgumentException - if the length of the fields array differs from the length of the flags array

      • parse

        public static Query parse​(Version matchVersion,
                          String[] queries,
                          String[] fields,
                          BooleanClause.Occur[] flags,
                          Analyzer analyzer)
                   throws ParseException
        Parses a query, searching on the fields specified. Use this if you need to specify certain fields as required, and others as prohibited. 

         Usage:
 
 String[] query = {"query1", "query2", "query3"};
 String[] fields = {"filename", "contents", "description"};
 BooleanClause.Occur[] flags = {BooleanClause.Occur.SHOULD,
                BooleanClause.Occur.MUST,
                BooleanClause.Occur.MUST_NOT};
 MultiFieldQueryParser.parse(query, fields, flags, analyzer);

        The code above would construct a query: 

         
 (filename:query1) +(contents:query2) -(description:query3)
        Parameters:
        matchVersion - Lucene version to match; this is passed through to QueryParser.
        queries - Queries string to parse
        fields - Fields to search on
        flags - Flags describing the fields
        analyzer - Analyzer to use
        Throws:
        ParseException - if query parsing fails
        IllegalArgumentException - if the length of the queries, fields, and flags array differ