package org.apache.lucene.queryParser.core.processors;
/**
* 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 java.util.Iterator;
import java.util.List;
import org.apache.lucene.queryParser.core.QueryNodeException;
import org.apache.lucene.queryParser.core.nodes.DeletedQueryNode;
import org.apache.lucene.queryParser.core.nodes.MatchNoDocsQueryNode;
import org.apache.lucene.queryParser.core.nodes.QueryNode;
/**
* A {@link QueryNodeProcessorPipeline} class removes every instance of
* {@link DeletedQueryNode} from a query node tree. If the resulting root node
* is a {@link DeletedQueryNode}, {@link MatchNoDocsQueryNode} is returned.
*
*/
public class RemoveDeletedQueryNodesProcessor extends QueryNodeProcessorImpl {
public RemoveDeletedQueryNodesProcessor() {
// empty constructor
}
@Override
public QueryNode process(QueryNode queryTree) throws QueryNodeException {
queryTree = super.process(queryTree);
if (queryTree instanceof DeletedQueryNode
&& !(queryTree instanceof MatchNoDocsQueryNode)) {
return new MatchNoDocsQueryNode();
}
return queryTree;
}
@Override
protected QueryNode postProcessNode(QueryNode node) throws QueryNodeException {
if (!node.isLeaf()) {
List<QueryNode> children = node.getChildren();
boolean removeBoolean = false;
if (children == null || children.size() == 0) {
removeBoolean = true;
} else {
removeBoolean = true;
for (Iterator<QueryNode> it = children.iterator(); it.hasNext();) {
if (!(it.next() instanceof DeletedQueryNode)) {
removeBoolean = false;
break;
}
}
}
if (removeBoolean) {
return new DeletedQueryNode();
}
}
return node;
}
@Override
protected List<QueryNode> setChildrenOrder(List<QueryNode> children)
throws QueryNodeException {
for (int i = 0; i < children.size(); i++) {
if (children.get(i) instanceof DeletedQueryNode) {
children.remove(i--);
}
}
return children;
}
@Override
protected QueryNode preProcessNode(QueryNode node) throws QueryNodeException {
return node;
}
}