org.apache.lucene.queryparser.ext.ParserExtension Maven / Gradle / Ivy
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* 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.
*/
package org.apache.lucene.queryparser.ext;
import org.apache.lucene.queryparser.classic.ParseException;
import org.apache.lucene.search.Query;
/**
* This class represents an extension base class to the Lucene standard {@link
* org.apache.lucene.queryparser.classic.QueryParser}. The {@link
* org.apache.lucene.queryparser.classic.QueryParser} is generated by the JavaCC parser generator.
* Changing or adding functionality or syntax in the standard query parser requires changes to the
* JavaCC source file. To enable extending the standard query parser without changing the JavaCC
* sources and re-generate the parser the {@link ParserExtension} can be customized and plugged into
* an instance of {@link ExtendableQueryParser}, a direct subclass of {@link
* org.apache.lucene.queryparser.classic.QueryParser}.
*
* @see Extensions
* @see ExtendableQueryParser
*/
public abstract class ParserExtension {
/**
* Processes the given {@link ExtensionQuery} and returns a corresponding {@link Query} instance.
* Subclasses must either return a {@link Query} instance or raise a {@link ParseException}. This
* method must not return null.
*
* @param query the extension query
* @return a new query instance
* @throws ParseException if the query can not be parsed.
*/
public abstract Query parse(final ExtensionQuery query) throws ParseException;
}