org.apache.lucene.queryParser
Class MultiFieldQueryParser

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

All Implemented Interfaces:

QueryParserConstants

public class MultiFieldQueryParser
extends QueryParser

A QueryParser which constructs queries to search multiple fields.

Version:

$Revision: 692921 $

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.lucene.queryParser.QueryParser

QueryParser.Operator

Field Summary

protected Map	boosts
protected String[]	fields

Fields inherited from class org.apache.lucene.queryParser.QueryParser

AND_OPERATOR, jj_nt, OR_OPERATOR, token, token_source

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

_ESCAPED_CHAR, _NUM_CHAR, _QUOTED_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

MultiFieldQueryParser(String[] fields, Analyzer analyzer)
Creates a MultiFieldQueryParser.

MultiFieldQueryParser(String[] fields, Analyzer analyzer, Map boosts)
Creates a MultiFieldQueryParser.

Method Summary

protected Query	getFieldQuery(String field, String queryText)
protected Query	getFieldQuery(String field, String queryText, int slop) Base implementation delegates to QueryParser.getFieldQuery(String,String).
protected Query	getFuzzyQuery(String field, String termStr, float minSimilarity) Factory method for generating a query (similar to QueryParser.getWildcardQuery(java.lang.String, java.lang.String)).
protected Query	getPrefixQuery(String field, String termStr) Factory method for generating a query (similar to QueryParser.getWildcardQuery(java.lang.String, java.lang.String)).
protected Query	getRangeQuery(String field, String part1, String part2, boolean inclusive)
protected Query	getWildcardQuery(String field, String termStr) Factory method for generating a query.
static Query	parse(String[] queries, String[] fields, Analyzer analyzer) Parses a query which searches on the fields specified.
static Query	parse(String[] queries, String[] fields, BooleanClause.Occur[] flags, Analyzer analyzer) Parses a query, searching on the fields specified.
static Query	parse(String query, String[] fields, BooleanClause.Occur[] flags, Analyzer analyzer) Parses a query, searching on the fields specified.

Methods inherited from class org.apache.lucene.queryParser.QueryParser

addClause, addClause, Clause, Conjunction, disable_tracing, enable_tracing, escape, generateParseException, getAllowLeadingWildcard, getAnalyzer, getBooleanQuery, getBooleanQuery, getBooleanQuery, getBooleanQuery, getDateResolution, getDefaultOperator, getEnablePositionIncrements, getField, getFuzzyMinSim, getFuzzyPrefixLength, getLocale, getLowercaseExpandedTerms, getNextToken, getPhraseSlop, getRangeCollator, getToken, getUseOldRangeQuery, main, Modifiers, newBooleanClause, newBooleanQuery, newFuzzyQuery, newMatchAllDocsQuery, newMultiPhraseQuery, newPhraseQuery, newPrefixQuery, newRangeQuery, newTermQuery, newWildcardQuery, parse, Query, ReInit, ReInit, setAllowLeadingWildcard, setDateResolution, setDateResolution, setDefaultOperator, setEnablePositionIncrements, setFuzzyMinSim, setFuzzyPrefixLength, setLocale, setLowercaseExpandedTerms, setPhraseSlop, setRangeCollator, setUseOldRangeQuery, Term, TopLevelQuery

Methods inherited from class java.lang.Object

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

Field Detail

fields

protected String[] fields

boosts

protected Map boosts

Constructor Detail

MultiFieldQueryParser

public MultiFieldQueryParser(String[] fields,
                             Analyzer analyzer,
                             Map 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(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

getFieldQuery

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

Description copied from class: QueryParser

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

Overrides:

getFieldQuery in class QueryParser

Throws:

ParseException - throw in overridden method to disallow

getFieldQuery

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

Overrides:

getFieldQuery in class QueryParser

Throws:

ParseException - throw in overridden method to disallow

getFuzzyQuery

protected Query getFuzzyQuery(String field,
                              String termStr,
                              float minSimilarity)
                       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 has the fuzzy suffix (~) appended.

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 - throw in overridden method to disallow

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

getRangeQuery

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

Overrides:

getRangeQuery in class QueryParser

Throws:

ParseException - throw in overridden method to disallow

parse

public static Query parse(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:

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(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:

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(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:

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