package org.apache.lucene.queryparser.flexible.precedence.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.ArrayList;
import java.util.List;
import org.apache.lucene.queryparser.flexible.precedence.PrecedenceQueryParser;
import org.apache.lucene.queryparser.flexible.standard.config.StandardQueryConfigHandler;
import org.apache.lucene.queryparser.flexible.standard.config.StandardQueryConfigHandler.ConfigurationKeys;
import org.apache.lucene.queryparser.flexible.standard.config.StandardQueryConfigHandler.Operator;
import org.apache.lucene.queryparser.flexible.core.QueryNodeException;
import org.apache.lucene.queryparser.flexible.core.nodes.*;
import org.apache.lucene.queryparser.flexible.core.processors.QueryNodeProcessorImpl;
import org.apache.lucene.queryparser.flexible.core.nodes.ModifierQueryNode.Modifier;
/**
* <p>
* This processor is used to apply the correct {@link ModifierQueryNode} to {@link BooleanQueryNode}s children.
* </p>
* <p>
* It walks through the query node tree looking for {@link BooleanQueryNode}s. If an {@link AndQueryNode} is found,
* every child, which is not a {@link ModifierQueryNode} or the {@link ModifierQueryNode}
* is {@link Modifier#MOD_NONE}, becomes a {@link Modifier#MOD_REQ}. For any other
* {@link BooleanQueryNode} which is not an {@link OrQueryNode}, it checks the default operator is {@link Operator#AND},
* if it is, the same operation when an {@link AndQueryNode} is found is applied to it.
* </p>
*
* @see ConfigurationKeys#DEFAULT_OPERATOR
* @see PrecedenceQueryParser#setDefaultOperator
*/
public class BooleanModifiersQueryNodeProcessor extends QueryNodeProcessorImpl {
private ArrayList<QueryNode> childrenBuffer = new ArrayList<>();
private Boolean usingAnd = false;
public BooleanModifiersQueryNodeProcessor() {
// empty constructor
}
@Override
public QueryNode process(QueryNode queryTree) throws QueryNodeException {
Operator op = getQueryConfigHandler().get(ConfigurationKeys.DEFAULT_OPERATOR);
if (op == null) {
throw new IllegalArgumentException(
"StandardQueryConfigHandler.ConfigurationKeys.DEFAULT_OPERATOR should be set on the QueryConfigHandler");
}
this.usingAnd = StandardQueryConfigHandler.Operator.AND == op;
return super.process(queryTree);
}
@Override
protected QueryNode postProcessNode(QueryNode node) throws QueryNodeException {
if (node instanceof AndQueryNode) {
this.childrenBuffer.clear();
List<QueryNode> children = node.getChildren();
for (QueryNode child : children) {
this.childrenBuffer.add(applyModifier(child, ModifierQueryNode.Modifier.MOD_REQ));
}
node.set(this.childrenBuffer);
} else if (this.usingAnd && node instanceof BooleanQueryNode
&& !(node instanceof OrQueryNode)) {
this.childrenBuffer.clear();
List<QueryNode> children = node.getChildren();
for (QueryNode child : children) {
this.childrenBuffer.add(applyModifier(child, ModifierQueryNode.Modifier.MOD_REQ));
}
node.set(this.childrenBuffer);
}
return node;
}
private QueryNode applyModifier(QueryNode node, ModifierQueryNode.Modifier mod) {
// check if modifier is not already defined and is default
if (!(node instanceof ModifierQueryNode)) {
return new ModifierQueryNode(node, mod);
} else {
ModifierQueryNode modNode = (ModifierQueryNode) node;
if (modNode.getModifier() == ModifierQueryNode.Modifier.MOD_NONE) {
return new ModifierQueryNode(modNode.getChild(), mod);
}
}
return node;
}
@Override
protected QueryNode preProcessNode(QueryNode node) throws QueryNodeException {
return node;
}
@Override
protected List<QueryNode> setChildrenOrder(List<QueryNode> children)
throws QueryNodeException {
return children;
}
}