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org.apache.lucene.queryParser
Class MultiFieldQueryParser

java.lang.Object
  extended by org.apache.lucene.queryParser.QueryParser
      extended by 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: 965592 $

Nested Class Summary
 
Nested classes/interfaces inherited from class org.apache.lucene.queryParser.QueryParser
QueryParser.Operator
 
Field Summary
protected  Map<String,Float> 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(Version matchVersion, String[] fields, Analyzer analyzer)
          Creates a MultiFieldQueryParser.
MultiFieldQueryParser(Version matchVersion, String[] fields, Analyzer analyzer, Map<String,Float> boosts)
          Creates a MultiFieldQueryParser.
 
Method Summary
protected  Query getFieldQuery(String field, String queryText, boolean quoted)
           
protected  Query getFieldQuery(String field, String queryText, int slop)
          Base implementation delegates to QueryParser.getFieldQuery(String,String,boolean).
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(Version matchVersion, String[] queries, String[] fields, Analyzer analyzer)
          Parses a query which searches on the fields specified.
static Query parse(Version matchVersion, String[] queries, String[] fields, BooleanClause.Occur[] flags, Analyzer analyzer)
          Parses a query, searching on the fields specified.
static Query parse(Version matchVersion, 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, Clause, Conjunction, disable_tracing, enable_tracing, escape, generateParseException, getAllowLeadingWildcard, getAnalyzer, getAutoGeneratePhraseQueries, getBooleanQuery, getBooleanQuery, getDateResolution, getDefaultOperator, getEnablePositionIncrements, getField, getFieldQuery, getFuzzyMinSim, getFuzzyPrefixLength, getLocale, getLowercaseExpandedTerms, getMultiTermRewriteMethod, getNextToken, getPhraseSlop, getRangeCollator, getToken, main, Modifiers, newBooleanClause, newBooleanQuery, newFuzzyQuery, newMatchAllDocsQuery, newMultiPhraseQuery, newPhraseQuery, newPrefixQuery, newRangeQuery, newTermQuery, newWildcardQuery, parse, Query, ReInit, ReInit, setAllowLeadingWildcard, setAutoGeneratePhraseQueries, setDateResolution, setDateResolution, setDefaultOperator, setEnablePositionIncrements, setFuzzyMinSim, setFuzzyPrefixLength, setLocale, setLowercaseExpandedTerms, setMultiTermRewriteMethod, setPhraseSlop, setRangeCollator, 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<String,Float> boosts
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

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,boolean). 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,
                              boolean quoted)
                       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(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
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