org.apache.lucene.queryParser
Class QueryParser

java.lang.Object
  org.apache.lucene.queryParser.QueryParser

All Implemented Interfaces:

QueryParserConstants

Direct Known Subclasses:

AnalyzingQueryParser, MultiFieldQueryParser

public class QueryParser
extends 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.

Author:

Brian Goetz, Peter Halacsy, Tatu Saloranta

Nested Class Summary

static class

QueryParser.Operator The default operator for parsing queries.

Field Summary

static QueryParser.Operator	AND_OPERATOR Alternative form of QueryParser.Operator.AND
Token	jj_nt
boolean	lookingAhead
static QueryParser.Operator	OR_OPERATOR Alternative form of QueryParser.Operator.OR
Token	token
QueryParserTokenManager	token_source

Fields inherited from interface org.apache.lucene.queryParser.QueryParserConstants

_ESCAPED_CHAR, _NUM_CHAR, _TERM_CHAR, _TERM_START_CHAR, _WHITESPACE, AND, Boost, CARAT, COLON, DEFAULT, EOF, FUZZY_SLOP, LPAREN, MINUS, NOT, NUMBER, OR, PLUS, PREFIXTERM, QUOTED, RangeEx, RANGEEX_END, RANGEEX_GOOP, RANGEEX_QUOTED, RANGEEX_START, RANGEEX_TO, RangeIn, RANGEIN_END, RANGEIN_GOOP, RANGEIN_QUOTED, RANGEIN_START, RANGEIN_TO, RPAREN, STAR, TERM, tokenImage, WILDTERM

Constructor Summary

QueryParser(CharStream stream)

QueryParser(QueryParserTokenManager tm)

QueryParser(String f, Analyzer a)
Constructs a query parser.

Method Summary

protected void	addClause(Vector clauses, int conj, int mods, Query q)
Query	Clause(String field)
int	Conjunction()
void	disable_tracing()
void	enable_tracing()
static String	escape(String s) Returns a String where those characters that QueryParser expects to be escaped are escaped by a preceding \.
ParseException	generateParseException()
boolean	getAllowLeadingWildcard()
Analyzer	getAnalyzer()
protected Query	getBooleanQuery(Vector clauses) Factory method for generating query, given a set of clauses.
protected Query	getBooleanQuery(Vector clauses, boolean disableCoord) Factory method for generating query, given a set of clauses.
DateTools.Resolution	getDateResolution(String fieldName) Returns the date resolution that is used by RangeQueries for the given field.
QueryParser.Operator	getDefaultOperator() Gets implicit operator setting, which will be either AND_OPERATOR or OR_OPERATOR.
boolean	getEnablePositionIncrements()
String	getField()
protected Query	getFieldQuery(String field, String queryText)
protected Query	getFieldQuery(String field, String queryText, int slop) Base implementation delegates to getFieldQuery(String,String).
float	getFuzzyMinSim() Get the minimal similarity for fuzzy queries.
int	getFuzzyPrefixLength() Get the prefix length for fuzzy queries.
protected Query	getFuzzyQuery(String field, String termStr, float minSimilarity) Factory method for generating a query (similar to getWildcardQuery(java.lang.String, java.lang.String)).
Locale	getLocale() Returns current locale, allowing access by subclasses.
boolean	getLowercaseExpandedTerms()
Token	getNextToken()
int	getPhraseSlop() Gets the default slop for phrases.
protected Query	getPrefixQuery(String field, String termStr) Factory method for generating a query (similar to getWildcardQuery(java.lang.String, java.lang.String)).
protected Query	getRangeQuery(String field, String part1, String part2, boolean inclusive)
Token	getToken(int index)
boolean	getUseOldRangeQuery()
protected Query	getWildcardQuery(String field, String termStr) Factory method for generating a query.
static void	main(String[] args) Command line tool to test QueryParser, using SimpleAnalyzer.
int	Modifiers()
Query	parse(String query) Parses a query string, returning a Query.
Query	Query(String field)
void	ReInit(CharStream stream)
void	ReInit(QueryParserTokenManager tm)
void	setAllowLeadingWildcard(boolean allowLeadingWildcard) Set to true to allow leading wildcard characters.
void	setDateResolution(DateTools.Resolution dateResolution) Sets the default date resolution used by RangeQueries for fields for which no specific date resolutions has been set.
void	setDateResolution(String fieldName, DateTools.Resolution dateResolution) Sets the date resolution used by RangeQueries for a specific field.
void	setDefaultOperator(QueryParser.Operator op) Sets the boolean operator of the QueryParser.
void	setEnablePositionIncrements(boolean enable) Set to true to enable position increments in result query.
void	setFuzzyMinSim(float fuzzyMinSim) Set the minimum similarity for fuzzy queries.
void	setFuzzyPrefixLength(int fuzzyPrefixLength) Set the prefix length for fuzzy queries.
void	setLocale(Locale locale) Set locale used by date range parsing.
void	setLowercaseExpandedTerms(boolean lowercaseExpandedTerms) Whether terms of wildcard, prefix, fuzzy and range queries are to be automatically lower-cased or not.
void	setPhraseSlop(int phraseSlop) Sets the default slop for phrases.
void	setUseOldRangeQuery(boolean useOldRangeQuery) By default QueryParser uses new ConstantScoreRangeQuery in preference to RangeQuery for range queries.
Query	Term(String field)
Query	TopLevelQuery(String field)

Methods inherited from class java.lang.Object

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

Field Detail

AND_OPERATOR

public static final QueryParser.Operator AND_OPERATOR

Alternative form of QueryParser.Operator.AND

OR_OPERATOR

public static final QueryParser.Operator OR_OPERATOR

Alternative form of QueryParser.Operator.OR

token_source

public QueryParserTokenManager token_source

token

public Token token

jj_nt

public Token jj_nt

lookingAhead

public boolean lookingAhead

Constructor Detail

QueryParser

public QueryParser(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)

QueryParser

public QueryParser(QueryParserTokenManager tm)

Method Detail

parse

public Query parse(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 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.

getAllowLeadingWildcard

public boolean getAllowLeadingWildcard()

See Also:

setAllowLeadingWildcard(boolean)

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.

getEnablePositionIncrements

public boolean getEnablePositionIncrements()

See Also:

setEnablePositionIncrements(boolean)

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.

getLowercaseExpandedTerms

public boolean getLowercaseExpandedTerms()

See Also:

setLowercaseExpandedTerms(boolean)

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.

getUseOldRangeQuery

public boolean getUseOldRangeQuery()

See Also:

setUseOldRangeQuery(boolean)

setLocale

public void setLocale(Locale locale)

Set locale used by date range parsing.

getLocale

public 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(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(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.

addClause

protected void addClause(Vector clauses,
                         int conj,
                         int mods,
                         Query q)

getFieldQuery

protected Query getFieldQuery(String field,
                              String queryText)
                       throws ParseException

Throws:

ParseException - throw in overridden method to disallow

getFieldQuery

protected Query getFieldQuery(String field,
                              String queryText,
                              int slop)
                       throws ParseException

Base implementation delegates to getFieldQuery(String,String). This method may be overridden, for example, to return a SpanNearQuery instead of a PhraseQuery.

Throws:

ParseException - throw in overridden method to disallow

getRangeQuery

protected Query getRangeQuery(String field,
                              String part1,
                              String part2,
                              boolean inclusive)
                       throws ParseException

Throws:

ParseException - throw in overridden method to disallow

getBooleanQuery

protected Query getBooleanQuery(Vector clauses)
                         throws ParseException

Factory method for generating query, given a set of clauses. By default creates a boolean query composed of clauses passed in. Can be overridden by extending classes, to modify query being returned.

Parameters:

clauses - Vector that contains BooleanClause instances to join.

Returns:

Resulting Query object.

Throws:

ParseException - throw in overridden method to disallow

getBooleanQuery

protected Query getBooleanQuery(Vector clauses,
                                boolean disableCoord)
                         throws ParseException

Factory method for generating query, given a set of clauses. By default creates a boolean query composed of clauses passed in. Can be overridden by extending classes, to modify query being returned.

Parameters:

clauses - Vector that contains BooleanClause instances to join.

disableCoord - true if coord scoring should be disabled.

Returns:

Resulting Query object.

Throws:

ParseException - throw in overridden method to disallow

getWildcardQuery

protected Query getWildcardQuery(String field,
                                 String termStr)
                          throws ParseException

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.

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

getPrefixQuery

protected Query getPrefixQuery(String field,
                               String termStr)
                        throws ParseException

Factory method for generating a query (similar to 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.

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

getFuzzyQuery

protected Query getFuzzyQuery(String field,
                              String termStr,
                              float minSimilarity)
                       throws ParseException

Factory method for generating a query (similar to getWildcardQuery(java.lang.String, java.lang.String)). Called when parser parses an input term token that has the fuzzy suffix (~) appended.

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 - throw in overridden method to disallow

escape

public static String escape(String s)

Returns a String where those characters that QueryParser expects to be escaped are escaped by a preceding \.

main

public static void main(String[] args)
                 throws Exception

Command line tool to test QueryParser, using SimpleAnalyzer. Usage:
java org.apache.lucene.queryParser.QueryParser <input>

Throws:

Exception

Conjunction

public final int Conjunction()
                      throws ParseException

Throws:

ParseException

Modifiers

public final int Modifiers()
                    throws ParseException

Throws:

ParseException

TopLevelQuery

public final Query TopLevelQuery(String field)
                          throws ParseException

Throws:

ParseException

Query

public final Query Query(String field)
                  throws ParseException

Throws:

ParseException

Clause

public final Query Clause(String field)
                   throws ParseException

Throws:

ParseException

Term

public final Query Term(String field)
                 throws ParseException

Throws:

ParseException

ReInit

public void ReInit(CharStream stream)

ReInit

public void ReInit(QueryParserTokenManager tm)

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()