/*
* 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.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.QueryNode;
import org.apache.lucene.queryparser.flexible.core.nodes.SlopQueryNode;
import org.apache.lucene.queryparser.flexible.core.nodes.TokenizedPhraseQueryNode;
import org.apache.lucene.queryparser.flexible.core.processors.QueryNodeProcessorImpl;
import org.apache.lucene.queryparser.flexible.standard.config.StandardQueryConfigHandler.ConfigurationKeys;
import org.apache.lucene.queryparser.flexible.standard.nodes.MultiPhraseQueryNode;
/**
* This processor verifies if {@link ConfigurationKeys#PHRASE_SLOP}
* is defined in the {@link QueryConfigHandler}. If it is, it looks for every
* {@link TokenizedPhraseQueryNode} and {@link MultiPhraseQueryNode} that does
* not have any {@link SlopQueryNode} applied to it and creates an
* {@link SlopQueryNode} and apply to it. The new {@link SlopQueryNode} has the
* same slop value defined in the configuration.
*
* @see SlopQueryNode
* @see ConfigurationKeys#PHRASE_SLOP
*/
public class DefaultPhraseSlopQueryNodeProcessor extends QueryNodeProcessorImpl {
private boolean processChildren = true;
private int defaultPhraseSlop;
public DefaultPhraseSlopQueryNodeProcessor() {
// empty constructor
}
@Override
public QueryNode process(QueryNode queryTree) throws QueryNodeException {
QueryConfigHandler queryConfig = getQueryConfigHandler();
if (queryConfig != null) {
Integer defaultPhraseSlop = queryConfig.get(ConfigurationKeys.PHRASE_SLOP);
if (defaultPhraseSlop != null) {
this.defaultPhraseSlop = defaultPhraseSlop;
return super.process(queryTree);
}
}
return queryTree;
}
@Override
protected QueryNode postProcessNode(QueryNode node) throws QueryNodeException {
if (node instanceof TokenizedPhraseQueryNode
|| node instanceof MultiPhraseQueryNode) {
return new SlopQueryNode(node, this.defaultPhraseSlop);
}
return node;
}
@Override
protected QueryNode preProcessNode(QueryNode node) throws QueryNodeException {
if (node instanceof SlopQueryNode) {
this.processChildren = false;
}
return node;
}
@Override
protected void processChildren(QueryNode queryTree) throws QueryNodeException {
if (this.processChildren) {
super.processChildren(queryTree);
} else {
this.processChildren = true;
}
}
@Override
protected List<QueryNode> setChildrenOrder(List<QueryNode> children)
throws QueryNodeException {
return children;
}
}