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/tags/release-0.0.0-rc0/hive/external/ql/src/java/org/apache/hadoop/hive/ql/lib/Dispatcher.java

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Java | 47 lines | 7 code | 6 blank | 34 comment | 0 complexity | 76d2efd227aaed330f8bfd6bb2421116 MD5 | raw file
 1/**
 2 * Licensed to the Apache Software Foundation (ASF) under one
 3 * or more contributor license agreements.  See the NOTICE file
 4 * distributed with this work for additional information
 5 * regarding copyright ownership.  The ASF licenses this file
 6 * to you under the Apache License, Version 2.0 (the
 7 * "License"); you may not use this file except in compliance
 8 * with the License.  You may obtain a copy of the License at
 9 *
10 *     http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 */
18
19package org.apache.hadoop.hive.ql.lib;
20
21import java.util.Stack;
22
23import org.apache.hadoop.hive.ql.parse.SemanticException;
24
25/**
26 * Dispatcher interface for Operators Used in operator graph walking to dispatch
27 * process/visitor functions for operators.
28 */
29public interface Dispatcher {
30
31  /**
32   * Dispatcher function.
33   *
34   * @param nd
35   *          operator to process.
36   * @param stack
37   *          operator stack to process.
38   * @param nodeOutputs
39   *          The argument list of outputs from processing other nodes that are
40   *          passed to this dispatcher from the walker.
41   * @return Object The return object from the processing call.
42   * @throws SemanticException
43   */
44  Object dispatch(Node nd, Stack<Node> stack, Object... nodeOutputs)
45      throws SemanticException;
46
47}