/**
* 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.hadoop.hive.ql.lib;
import java.util.Stack;
import org.apache.hadoop.hive.ql.parse.SemanticException;
/**
* Dispatcher interface for Operators Used in operator graph walking to dispatch
* process/visitor functions for operators.
*/
public interface Dispatcher {
/**
* Dispatcher function.
*
* @param nd
* operator to process.
* @param stack
* operator stack to process.
* @param nodeOutputs
* The argument list of outputs from processing other nodes that are
* passed to this dispatcher from the walker.
* @return Object The return object from the processing call.
* @throws SemanticException
*/
Object dispatch(Node nd, Stack<Node> stack, Object... nodeOutputs)
throws SemanticException;
}