org.apache.lucene.queryParser

Class MultiFieldQueryParser

public class MultiFieldQueryParser extends QueryParser

A QueryParser which constructs queries to search multiple fields.

Version: $Revision: 525682 $

Author: Kelvin Tan, Daniel Naber

Field Summary
protected Mapboosts
protected String[]fields
Constructor Summary
MultiFieldQueryParser(String[] fields, Analyzer analyzer, Map boosts)
Creates a MultiFieldQueryParser.
MultiFieldQueryParser(String[] fields, Analyzer analyzer)
Creates a MultiFieldQueryParser.
Method Summary
protected QuerygetFieldQuery(String field, String queryText, int slop)
protected QuerygetFieldQuery(String field, String queryText)
protected QuerygetFuzzyQuery(String field, String termStr, float minSimilarity)
protected QuerygetPrefixQuery(String field, String termStr)
protected QuerygetRangeQuery(String field, String part1, String part2, boolean inclusive)
protected QuerygetWildcardQuery(String field, String termStr)
static Queryparse(String[] queries, String[] fields, Analyzer analyzer)
Parses a query which searches on the fields specified.
static Queryparse(String query, String[] fields, BooleanClause.Occur[] flags, Analyzer analyzer)
Parses a query, searching on the fields specified.
static Queryparse(String[] queries, String[] fields, BooleanClause.Occur[] flags, Analyzer analyzer)
Parses a query, searching on the fields specified.

Field Detail

boosts

protected Map boosts

fields

protected String[] fields

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)

getFieldQuery

protected Query getFieldQuery(String field, String queryText)

getFuzzyQuery

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

getPrefixQuery

protected Query getPrefixQuery(String field, String termStr)

getRangeQuery

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

getWildcardQuery

protected Query getWildcardQuery(String field, String termStr)

parse

public static Query parse(String[] queries, String[] fields, Analyzer analyzer)
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)
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)
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

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