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/*
* 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.phoenix.parse;
import java.sql.SQLException;
import java.util.Collections;
import java.util.List;
import org.apache.phoenix.compile.ColumnResolver;
/**
*
* Node representing a CASE in SQL
*
*
* @since 0.1
*/
public class CaseParseNode extends CompoundParseNode {
CaseParseNode(List children) {
super(children);
}
@Override
public T accept(ParseNodeVisitor visitor) throws SQLException {
List l = Collections.emptyList();
if (visitor.visitEnter(this)) {
l = acceptChildren(visitor);
}
return visitor.visitLeave(this, l);
}
@Override
public void toSQL(ColumnResolver resolver, StringBuilder buf) {
buf.append("CASE ");
List children = getChildren();
for (int i = 0; i < children.size() - 1; i+=2) {
buf.append("WHEN ");
children.get(i+1).toSQL(resolver, buf);
buf.append(" THEN ");
children.get(i).toSQL(resolver, buf);
}
if (children.size() % 2 != 0) { // has ELSE
buf.append(" ELSE ");
children.get(children.size()-1).toSQL(resolver, buf);
}
buf.append(" END ");
}
}
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