package org.apache.lucene.queryParser.standard.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.List;
import org.apache.lucene.queryParser.core.QueryNodeException;
import org.apache.lucene.queryParser.core.nodes.BooleanQueryNode;
import org.apache.lucene.queryParser.core.nodes.ModifierQueryNode;
import org.apache.lucene.queryParser.core.nodes.QueryNode;
import org.apache.lucene.queryParser.core.nodes.ModifierQueryNode.Modifier;
import org.apache.lucene.queryParser.core.processors.QueryNodeProcessorImpl;
import org.apache.lucene.queryParser.standard.nodes.BooleanModifierNode;
/**
* This processor removes every {@link BooleanQueryNode} that contains only one
* child and returns this child. If this child is {@link ModifierQueryNode} that
* was defined by the user. A modifier is not defined by the user when it's a
* {@link BooleanModifierNode} <br/>
*
* @see ModifierQueryNode
*/
public class BooleanSingleChildOptimizationQueryNodeProcessor extends
QueryNodeProcessorImpl {
public BooleanSingleChildOptimizationQueryNodeProcessor() {
// empty constructor
}
@Override
protected QueryNode postProcessNode(QueryNode node) throws QueryNodeException {
if (node instanceof BooleanQueryNode) {
List<QueryNode> children = node.getChildren();
if (children != null && children.size() == 1) {
QueryNode child = children.get(0);
if (child instanceof ModifierQueryNode) {
ModifierQueryNode modNode = (ModifierQueryNode) child;
if (modNode instanceof BooleanModifierNode
|| modNode.getModifier() == Modifier.MOD_NONE) {
return child;
}
} else {
return child;
}
}
}
return node;
}
@Override
protected QueryNode preProcessNode(QueryNode node) throws QueryNodeException {
return node;
}
@Override
protected List<QueryNode> setChildrenOrder(List<QueryNode> children)
throws QueryNodeException {
return children;
}
}