package org.apache.lucene.queryParser;
/**
* Copyright 2004 The Apache Software Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.queryParser.CharStream;
import org.apache.lucene.queryParser.ParseException;
import org.apache.lucene.queryParser.QueryParser;
import org.apache.lucene.queryParser.QueryParserTokenManager;
import org.apache.lucene.search.BooleanQuery;
import org.apache.lucene.search.Query;
/**
* A QueryParser which constructs queries to search multiple fields.
*
* @author <a href="mailto:kelvin@relevanz.com">Kelvin Tan</a>
* @version $Revision: 1.4 $
*/
public class MultiFieldQueryParser extends QueryParser
{
public static final int NORMAL_FIELD = 0;
public static final int REQUIRED_FIELD = 1;
public static final int PROHIBITED_FIELD = 2;
public MultiFieldQueryParser(QueryParserTokenManager tm)
{
super(tm);
}
public MultiFieldQueryParser(CharStream stream)
{
super(stream);
}
public MultiFieldQueryParser(String f, Analyzer a)
{
super(f, a);
}
/**
* <p>
* Parses a query which searches on the fields specified.
* <p>
* If x fields are specified, this effectively constructs:
* <pre>
* <code>
* (field1:query) (field2:query) (field3:query)...(fieldx:query)
* </code>
* </pre>
*
* @param query Query string to parse
* @param fields Fields to search on
* @param analyzer Analyzer to use
* @throws ParseException if query parsing fails
* @throws TokenMgrError if query parsing fails
*/
public static Query parse(String query, String[] fields, Analyzer analyzer)
throws ParseException
{
BooleanQuery bQuery = new BooleanQuery();
for (int i = 0; i < fields.length; i++)
{
Query q = parse(query, fields[i], analyzer);
bQuery.add(q, false, false);
}
return bQuery;
}
/**
* <p>
* Parses a query, searching on the fields specified.
* Use this if you need to specify certain fields as required,
* and others as prohibited.
* <p><pre>
* Usage:
* <code>
* String[] fields = {"filename", "contents", "description"};
* int[] flags = {MultiFieldQueryParser.NORMAL FIELD,
* MultiFieldQueryParser.REQUIRED FIELD,
* MultiFieldQueryParser.PROHIBITED FIELD,};
* parse(query, fields, flags, analyzer);
* </code>
* </pre>
*<p>
* The code above would construct a query:
* <pre>
* <code>
* (filename:query) +(contents:query) -(description:query)
* </code>
* </pre>
*
* @param query Query string to parse
* @param fields Fields to search on
* @param flags Flags describing the fields
* @param analyzer Analyzer to use
* @throws ParseException if query parsing fails
* @throws TokenMgrError if query parsing fails
*/
public static Query parse(String query, String[] fields, int[] flags,
Analyzer analyzer)
throws ParseException
{
BooleanQuery bQuery = new BooleanQuery();
for (int i = 0; i < fields.length; i++)
{
Query q = parse(query, fields[i], analyzer);
int flag = flags[i];
switch (flag)
{
case REQUIRED_FIELD:
bQuery.add(q, true, false);
break;
case PROHIBITED_FIELD:
bQuery.add(q, false, true);
break;
default:
bQuery.add(q, false, false);
break;
}
}
return bQuery;
}
}
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