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.FieldQueryNode;
import org.apache.lucene.queryParser.core.nodes.FuzzyQueryNode;
import org.apache.lucene.queryParser.core.nodes.ParametricQueryNode;
import org.apache.lucene.queryParser.core.nodes.QueryNode;
import org.apache.lucene.queryParser.core.nodes.QuotedFieldQueryNode;
import org.apache.lucene.queryParser.core.processors.QueryNodeProcessorImpl;
import org.apache.lucene.queryParser.core.util.UnescapedCharSequence;
import org.apache.lucene.queryParser.standard.nodes.PrefixWildcardQueryNode;
import org.apache.lucene.queryParser.standard.nodes.WildcardQueryNode;
import org.apache.lucene.queryParser.standard.parser.StandardSyntaxParser;
import org.apache.lucene.search.PrefixQuery;
/**
* The {@link StandardSyntaxParser} creates {@link PrefixWildcardQueryNode} nodes which
* have values containing the prefixed wildcard. However, Lucene
* {@link PrefixQuery} cannot contain the prefixed wildcard. So, this processor
* basically removed the prefixed wildcard from the
* {@link PrefixWildcardQueryNode} value. <br/>
*
* @see PrefixQuery
* @see PrefixWildcardQueryNode
*/
public class WildcardQueryNodeProcessor extends QueryNodeProcessorImpl {
public WildcardQueryNodeProcessor() {
// empty constructor
}
protected QueryNode postProcessNode(QueryNode node) throws QueryNodeException {
// the old Lucene Parser ignores FuzzyQueryNode that are also PrefixWildcardQueryNode or WildcardQueryNode
// we do the same here, also ignore empty terms
if (node instanceof FieldQueryNode || node instanceof FuzzyQueryNode) {
FieldQueryNode fqn = (FieldQueryNode) node;
CharSequence text = fqn.getText();
// do not process wildcards for ParametricQueryNode and
// QuotedFieldQueryNode to reproduce the old parser behavior
if (fqn instanceof ParametricQueryNode
|| fqn instanceof QuotedFieldQueryNode
|| text.length() <= 0){
// Ignore empty terms
return node;
}
// Code below simulates the old lucene parser behavior for wildcards
if (isPrefixWildcard(text)) {
PrefixWildcardQueryNode prefixWildcardQN = new PrefixWildcardQueryNode(fqn);
return prefixWildcardQN;
} else if (isWildcard(text)){
WildcardQueryNode wildcardQN = new WildcardQueryNode(fqn);
return wildcardQN;
}
}
return node;
}
private boolean isWildcard(CharSequence text) {
if (text ==null || text.length() <= 0) return false;
// If a un-escaped '*' or '?' if found return true
// start at the end since it's more common to put wildcards at the end
for(int i=text.length()-1; i>=0; i--){
if ((text.charAt(i) == '*' || text.charAt(i) == '?') && !UnescapedCharSequence.wasEscaped(text, i)){
return true;
}
}
return false;
}
private boolean isPrefixWildcard(CharSequence text) {
if (text == null || text.length() <= 0 || !isWildcard(text)) return false;
// Validate last character is a '*' and was not escaped
// If single '*' is is a wildcard not prefix to simulate old queryparser
if (text.charAt(text.length()-1) != '*') return false;
if (UnescapedCharSequence.wasEscaped(text, text.length()-1)) return false;
if (text.length() == 1) return false;
// Only make a prefix if there is only one single star at the end and no '?' or '*' characters
// If single wildcard return false to mimic old queryparser
for(int i=0; i<text.length(); i++){
if (text.charAt(i) == '?') return false;
if (text.charAt(i) == '*' && !UnescapedCharSequence.wasEscaped(text, i)){
if (i == text.length()-1)
return true;
else
return false;
}
}
return false;
}
protected QueryNode preProcessNode(QueryNode node) throws QueryNodeException {
return node;
}
protected List<QueryNode> setChildrenOrder(List<QueryNode> children)
throws QueryNodeException {
return children;
}
}