package org.apache.lucene.queryParser.standard;
/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.core.QueryNodeException;
import org.apache.lucene.search.BooleanClause;
import org.apache.lucene.search.BooleanQuery;
import org.apache.lucene.search.Query;
/**
* This class defines utility methods to (help) parse query strings into
* {@link Query} objects.
*/
final public class QueryParserUtil {
/**
* Parses a query which searches on the fields specified.
* <p>
* If x fields are specified, this effectively constructs:
*
* <pre>
* <code>
* (field1:query1) (field2:query2) (field3:query3)...(fieldx:queryx)
* </code>
* </pre>
*
* @param queries
* Queries strings to parse
* @param fields
* Fields to search on
* @param analyzer
* Analyzer to use
* @throws IllegalArgumentException
* if the length of the queries array differs from the length of the
* fields array
*/
public static Query parse(String[] queries, String[] fields, Analyzer analyzer)
throws QueryNodeException {
if (queries.length != fields.length)
throw new IllegalArgumentException("queries.length != fields.length");
BooleanQuery bQuery = new BooleanQuery();
StandardQueryParser qp = new StandardQueryParser();
qp.setAnalyzer(analyzer);
for (int i = 0; i < fields.length; i++) {
Query q = qp.parse(queries[i], fields[i]);
if (q != null && // q never null, just being defensive
(!(q instanceof BooleanQuery) || ((BooleanQuery) q).getClauses().length > 0)) {
bQuery.add(q, BooleanClause.Occur.SHOULD);
}
}
return bQuery;
}
/**
* 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"};
* BooleanClause.Occur[] flags = {BooleanClause.Occur.SHOULD,
* BooleanClause.Occur.MUST,
* BooleanClause.Occur.MUST_NOT};
* MultiFieldQueryParser.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 IllegalArgumentException
* if the length of the fields array differs from the length of the
* flags array
*/
public static Query parse(String query, String[] fields,
BooleanClause.Occur[] flags, Analyzer analyzer) throws QueryNodeException {
if (fields.length != flags.length)
throw new IllegalArgumentException("fields.length != flags.length");
BooleanQuery bQuery = new BooleanQuery();
StandardQueryParser qp = new StandardQueryParser();
qp.setAnalyzer(analyzer);
for (int i = 0; i < fields.length; i++) {
Query q = qp.parse(query, fields[i]);
if (q != null && // q never null, just being defensive
(!(q instanceof BooleanQuery) || ((BooleanQuery) q).getClauses().length > 0)) {
bQuery.add(q, flags[i]);
}
}
return bQuery;
}
/**
* 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[] 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);
* </code>
* </pre>
*<p>
* The code above would construct a query:
*
* <pre>
* <code>
* (filename:query1) +(contents:query2) -(description:query3)
* </code>
* </pre>
*
* @param queries
* Queries string to parse
* @param fields
* Fields to search on
* @param flags
* Flags describing the fields
* @param analyzer
* Analyzer to use
* @throws IllegalArgumentException
* if the length of the queries, fields, and flags array differ
*/
public static Query parse(String[] queries, String[] fields,
BooleanClause.Occur[] flags, Analyzer analyzer) throws QueryNodeException {
if (!(queries.length == fields.length && queries.length == flags.length))
throw new IllegalArgumentException(
"queries, fields, and flags array have have different length");
BooleanQuery bQuery = new BooleanQuery();
StandardQueryParser qp = new StandardQueryParser();
qp.setAnalyzer(analyzer);
for (int i = 0; i < fields.length; i++) {
Query q = qp.parse(queries[i], fields[i]);
if (q != null && // q never null, just being defensive
(!(q instanceof BooleanQuery) || ((BooleanQuery) q).getClauses().length > 0)) {
bQuery.add(q, flags[i]);
}
}
return bQuery;
}
/**
* Returns a String where those characters that TextParser expects to be
* escaped are escaped by a preceding <code>\</code>.
*/
public static String escape(String s) {
StringBuilder sb = new StringBuilder();
for (int i = 0; i < s.length(); i++) {
char c = s.charAt(i);
// These characters are part of the query syntax and must be escaped
if (c == '\\' || c == '+' || c == '-' || c == '!' || c == '(' || c == ')'
|| c == ':' || c == '^' || c == '[' || c == ']' || c == '\"'
|| c == '{' || c == '}' || c == '~' || c == '*' || c == '?'
|| c == '|' || c == '&') {
sb.append('\\');
}
sb.append(c);
}
return sb.toString();
}
}