/*
* 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.standard.processors;
import java.util.ArrayList;
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.AndQueryNode;
import org.apache.lucene.queryparser.flexible.core.nodes.BooleanQueryNode;
import org.apache.lucene.queryparser.flexible.core.nodes.ModifierQueryNode;
import org.apache.lucene.queryparser.flexible.core.nodes.ModifierQueryNode.Modifier;
import org.apache.lucene.queryparser.flexible.core.nodes.QueryNode;
import org.apache.lucene.queryparser.flexible.core.processors.QueryNodeProcessor;
import org.apache.lucene.queryparser.flexible.precedence.processors.BooleanModifiersQueryNodeProcessor;
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.standard.nodes.BooleanModifierNode;
import org.apache.lucene.queryparser.flexible.standard.parser.StandardSyntaxParser;
/**
* <p>
* This processor is used to apply the correct {@link ModifierQueryNode} to
* {@link BooleanQueryNode}s children. This is a variant of
* {@link BooleanModifiersQueryNodeProcessor} which ignores precedence.
* </p>
* <p>
* The {@link StandardSyntaxParser} knows the rules of precedence, but lucene
* does not. e.g. <code>(A AND B OR C AND D)</code> ist treated like
* <code>(+A +B +C +D)</code>.
* </p>
* <p>
* This processor 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 default
* {@link BooleanQueryNode}, 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. Each {@link BooleanQueryNode}
* which direct parent is also a {@link BooleanQueryNode} is removed (to ignore
* the rules of precedence).
* </p>
*
* @see ConfigurationKeys#DEFAULT_OPERATOR
* @see BooleanModifiersQueryNodeProcessor
*/
public class BooleanQuery2ModifierNodeProcessor implements QueryNodeProcessor {
final static String TAG_REMOVE = "remove";
final static String TAG_MODIFIER = "wrapWithModifier";
final static String TAG_BOOLEAN_ROOT = "booleanRoot";
QueryConfigHandler queryConfigHandler;
private final ArrayList<QueryNode> childrenBuffer = new ArrayList<>();
private Boolean usingAnd = false;
public BooleanQuery2ModifierNodeProcessor() {
// 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 processIteration(queryTree);
}
protected void processChildren(QueryNode queryTree) throws QueryNodeException {
List<QueryNode> children = queryTree.getChildren();
if (children != null && children.size() > 0) {
for (QueryNode child : children) {
child = processIteration(child);
}
}
}
private QueryNode processIteration(QueryNode queryTree)
throws QueryNodeException {
queryTree = preProcessNode(queryTree);
processChildren(queryTree);
queryTree = postProcessNode(queryTree);
return queryTree;
}
protected void fillChildrenBufferAndApplyModifiery(QueryNode parent) {
for (QueryNode node : parent.getChildren()) {
if (node.containsTag(TAG_REMOVE)) {
fillChildrenBufferAndApplyModifiery(node);
} else if (node.containsTag(TAG_MODIFIER)) {
childrenBuffer.add(applyModifier(node,
(Modifier) node.getTag(TAG_MODIFIER)));
} else {
childrenBuffer.add(node);
}
}
}
protected QueryNode postProcessNode(QueryNode node) throws QueryNodeException {
if (node.containsTag(TAG_BOOLEAN_ROOT)) {
this.childrenBuffer.clear();
fillChildrenBufferAndApplyModifiery(node);
node.set(childrenBuffer);
}
return node;
}
protected QueryNode preProcessNode(QueryNode node) throws QueryNodeException {
QueryNode parent = node.getParent();
if (node instanceof BooleanQueryNode) {
if (parent instanceof BooleanQueryNode) {
node.setTag(TAG_REMOVE, Boolean.TRUE); // no precedence
} else {
node.setTag(TAG_BOOLEAN_ROOT, Boolean.TRUE);
}
} else if (parent instanceof BooleanQueryNode) {
if ((parent instanceof AndQueryNode)
|| (usingAnd && isDefaultBooleanQueryNode(parent))) {
tagModifierButDoNotOverride(node, ModifierQueryNode.Modifier.MOD_REQ);
}
}
return node;
}
protected boolean isDefaultBooleanQueryNode(QueryNode toTest) {
return toTest != null && BooleanQueryNode.class.equals(toTest.getClass());
}
private QueryNode applyModifier(QueryNode node, Modifier mod) {
// check if modifier is not already defined and is default
if (!(node instanceof ModifierQueryNode)) {
return new BooleanModifierNode(node, mod);
} else {
ModifierQueryNode modNode = (ModifierQueryNode) node;
if (modNode.getModifier() == Modifier.MOD_NONE) {
return new ModifierQueryNode(modNode.getChild(), mod);
}
}
return node;
}
protected void tagModifierButDoNotOverride(QueryNode node, Modifier mod) {
if (node instanceof ModifierQueryNode) {
ModifierQueryNode modNode = (ModifierQueryNode) node;
if (modNode.getModifier() == Modifier.MOD_NONE) {
node.setTag(TAG_MODIFIER, mod);
}
} else {
node.setTag(TAG_MODIFIER, ModifierQueryNode.Modifier.MOD_REQ);
}
}
@Override
public void setQueryConfigHandler(QueryConfigHandler queryConfigHandler) {
this.queryConfigHandler = queryConfigHandler;
}
@Override
public QueryConfigHandler getQueryConfigHandler() {
return queryConfigHandler;
}
}