Documentation of 'org.apache.lucene.queryParser.QueryParser' Java class
QueryParser
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org.apache.lucene.queryParser

Class QueryParser

  • All Implemented Interfaces:
    QueryParserConstants
    Direct Known Subclasses:
    MultiFieldQueryParser

    public class QueryParser
extends java.lang.Object
implements QueryParserConstants
    This class is generated by JavaCC. The most important method is parse(String). The syntax for query strings is as follows: A Query is a series of clauses. A clause may be prefixed by:
    • a plus (+) or a minus (-) sign, indicating that the clause is required or prohibited respectively; or
    • a term followed by a colon, indicating the field to be searched. This enables one to construct queries which search multiple fields.
    A clause may be either:
    • a term, indicating all the documents that contain this term; or
    • a nested query, enclosed in parentheses. Note that this may be used with a +/- prefix to require any of a set of terms.
    Thus, in BNF, the query grammar is: 
       Query  ::= ( Clause )*
   Clause ::= ["+", "-"] [<TERM> ":"] ( <TERM> | "(" Query ")" )

    Examples of appropriately formatted queries can be found in the query syntax documentation.

    In RangeQuerys, QueryParser tries to detect date values, e.g. date:[6/1/2005 TO 6/4/2005] produces a range query that searches for "date" fields between 2005-06-01 and 2005-06-04. Note that the format of the accepted input depends on the locale. By default a date is converted into a search term using the deprecated DateField for compatibility reasons. To use the new DateTools to convert dates, a DateTools.Resolution has to be set.

    The date resolution that shall be used for RangeQueries can be set using setDateResolution(DateTools.Resolution) or setDateResolution(String, DateTools.Resolution). The former sets the default date resolution for all fields, whereas the latter can be used to set field specific date resolutions. Field specific date resolutions take, if set, precedence over the default date resolution.

    If you use neither DateField nor DateTools in your index, you can create your own query parser that inherits QueryParser and overwrites getRangeQuery(String, String, String, boolean) to use a different method for date conversion.

    Note that QueryParser is not thread-safe.

    • Constructor Detail

      • QueryParser

        public QueryParser(java.lang.String f,
                   Analyzer a)
        Constructs a query parser.
        Parameters:
        f - the default field for query terms.
        a - used to find terms in the query text.

      • QueryParser

        public QueryParser(CharStream stream)

    • Method Detail

      • parse

        public Query parse(java.lang.String query)
            throws ParseException
        Parses a query string, returning a Query.
        Parameters:
        query - the query string to be parsed.
        Throws:
        ParseException - if the parsing fails

      • getAnalyzer

        public Analyzer getAnalyzer()
        Returns:
        Returns the analyzer.

      • getField

        public java.lang.String getField()
        Returns:
        Returns the field.

      • getFuzzyMinSim

        public float getFuzzyMinSim()
        Get the minimal similarity for fuzzy queries.

      • setFuzzyMinSim

        public void setFuzzyMinSim(float fuzzyMinSim)
        Set the minimum similarity for fuzzy queries. Default is 0.5f.

      • getFuzzyPrefixLength

        public int getFuzzyPrefixLength()
        Get the prefix length for fuzzy queries.
        Returns:
        Returns the fuzzyPrefixLength.

      • setFuzzyPrefixLength

        public void setFuzzyPrefixLength(int fuzzyPrefixLength)
        Set the prefix length for fuzzy queries. Default is 0.
        Parameters:
        fuzzyPrefixLength - The fuzzyPrefixLength to set.

      • setPhraseSlop

        public void setPhraseSlop(int phraseSlop)
        Sets the default slop for phrases. If zero, then exact phrase matches are required. Default value is zero.

      • getPhraseSlop

        public int getPhraseSlop()
        Gets the default slop for phrases.

      • setAllowLeadingWildcard

        public void setAllowLeadingWildcard(boolean allowLeadingWildcard)
        Set to true to allow leading wildcard characters.

        When set, * or ? are allowed as the first character of a PrefixQuery and WildcardQuery. Note that this can produce very slow queries on big indexes.

        Default: false.

      • setEnablePositionIncrements

        public void setEnablePositionIncrements(boolean enable)
        Set to true to enable position increments in result query.

        When set, result phrase and multi-phrase queries will be aware of position increments. Useful when e.g. a StopFilter increases the position increment of the token that follows an omitted token.

        Default: false.

      • setDefaultOperator

        public void setDefaultOperator(QueryParser.Operator op)
        Sets the boolean operator of the QueryParser. In default mode (OR_OPERATOR) terms without any modifiers are considered optional: for example capital of Hungary is equal to capital OR of OR Hungary.
        In AND_OPERATOR mode terms are considered to be in conjuction: the above mentioned query is parsed as capital AND of AND Hungary

      • getDefaultOperator

        public QueryParser.Operator getDefaultOperator()
        Gets implicit operator setting, which will be either AND_OPERATOR or OR_OPERATOR.

      • setLowercaseExpandedTerms

        public void setLowercaseExpandedTerms(boolean lowercaseExpandedTerms)
        Whether terms of wildcard, prefix, fuzzy and range queries are to be automatically lower-cased or not. Default is true.

      • setUseOldRangeQuery

        public void setUseOldRangeQuery(boolean useOldRangeQuery)
        By default QueryParser uses new ConstantScoreRangeQuery in preference to RangeQuery for range queries. This implementation is generally preferable because it a) Runs faster b) Does not have the scarcity of range terms unduly influence score c) avoids any "TooManyBooleanClauses" exception. However, if your application really needs to use the old-fashioned RangeQuery and the above points are not required then set this option to true Default is false.

      • setLocale

        public void setLocale(java.util.Locale locale)
        Set locale used by date range parsing.

      • getLocale

        public java.util.Locale getLocale()
        Returns current locale, allowing access by subclasses.

      • setDateResolution

        public void setDateResolution(DateTools.Resolution dateResolution)
        Sets the default date resolution used by RangeQueries for fields for which no specific date resolutions has been set. Field specific resolutions can be set with setDateResolution(String, DateTools.Resolution).
        Parameters:
        dateResolution - the default date resolution to set

      • setDateResolution

        public void setDateResolution(java.lang.String fieldName,
                              DateTools.Resolution dateResolution)
        Sets the date resolution used by RangeQueries for a specific field.
        Parameters:
        fieldName - field for which the date resolution is to be set
        dateResolution - date resolution to set

      • getDateResolution

        public DateTools.Resolution getDateResolution(java.lang.String fieldName)
        Returns the date resolution that is used by RangeQueries for the given field. Returns null, if no default or field specific date resolution has been set for the given field.

      • escape

        public static java.lang.String escape(java.lang.String s)
        Returns a String where those characters that QueryParser expects to be escaped are escaped by a preceding \.

      • main

        public static void main(java.lang.String[] args)
                 throws java.lang.Exception
        Command line tool to test QueryParser, using SimpleAnalyzer. Usage:
        java org.apache.lucene.queryParser.QueryParser <input>
        Throws:
        java.lang.Exception

      • getNextToken

        public final Token getNextToken()

      • getToken

        public final Token getToken(int index)

      • generateParseException

        public ParseException generateParseException()

      • enable_tracing

        public final void enable_tracing()

      • disable_tracing

        public final void disable_tracing()
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