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

/**
 * 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.List;

/**
 * This interface defines the functions needed by the walkers and dispatchers.
 * These are implemented by the node of the graph that needs to be walked.
 */
public interface Node {

  /**
   * Gets the vector of children nodes. This is used in the graph walker
   * algorithms.
   * 
   * @return List<? extends Node>
   */
  List<? extends Node> getChildren();

  /**
   * Gets the name of the node. This is used in the rule dispatchers.
   * 
   * @return String
   */
  String getName();
}