/**
* 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.tajo.engine.planner.physical;
import java.util.Stack;
public class PhysicalPlanUtil {
public static <T extends PhysicalExec> T findExecutor(PhysicalExec plan, Class<? extends PhysicalExec> clazz)
throws PhysicalPlanningException {
return (T) new FindVisitor().visit(plan, new Stack<PhysicalExec>(), clazz);
}
private static class FindVisitor extends BasicPhysicalExecutorVisitor<Class<? extends PhysicalExec>, PhysicalExec> {
public PhysicalExec visit(PhysicalExec exec, Stack<PhysicalExec> stack, Class<? extends PhysicalExec> target)
throws PhysicalPlanningException {
if (target.isAssignableFrom(exec.getClass())) {
return exec;
} else {
return super.visit(exec, stack, target);
}
}
}
}