/*
* 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.flexible.spans;
import java.util.List;
import org.apache.lucene.queryparser.flexible.core.QueryNodeException;
import org.apache.lucene.queryparser.flexible.core.config.QueryConfigHandler;
import org.apache.lucene.queryparser.flexible.core.nodes.FieldableNode;
import org.apache.lucene.queryparser.flexible.core.nodes.QueryNode;
import org.apache.lucene.queryparser.flexible.core.processors.QueryNodeProcessorImpl;
/**
* This processor changes every field name of each {@link FieldableNode} query
* node contained in the query tree to the field name defined in the
* {@link UniqueFieldAttribute}. So, the {@link UniqueFieldAttribute} must be
* defined in the {@link QueryConfigHandler} object set in this processor,
* otherwise it throws an exception.
*
* @see UniqueFieldAttribute
*/
public class UniqueFieldQueryNodeProcessor extends QueryNodeProcessorImpl {
@Override
protected QueryNode postProcessNode(QueryNode node) throws QueryNodeException {
return node;
}
@Override
protected QueryNode preProcessNode(QueryNode node) throws QueryNodeException {
if (node instanceof FieldableNode) {
FieldableNode fieldNode = (FieldableNode) node;
QueryConfigHandler queryConfig = getQueryConfigHandler();
if (queryConfig == null) {
throw new IllegalArgumentException(
"A config handler is expected by the processor UniqueFieldQueryNodeProcessor!");
}
if (!queryConfig.has(SpansQueryConfigHandler.UNIQUE_FIELD)) {
throw new IllegalArgumentException(
"UniqueFieldAttribute should be defined in the config handler!");
}
String uniqueField = queryConfig.get(SpansQueryConfigHandler.UNIQUE_FIELD);
fieldNode.setField(uniqueField);
}
return node;
}
@Override
protected List<QueryNode> setChildrenOrder(List<QueryNode> children)
throws QueryNodeException {
return children;
}
}