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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  
19  package org.apache.giraph.master;
20  
21  import org.apache.giraph.conf.ImmutableClassesGiraphConfigurable;
22  
23  /**
24   * Observer for Master.
25   */
26  public interface MasterObserver extends ImmutableClassesGiraphConfigurable {
27    /**
28     * Before application begins.
29     */
30    void preApplication();
31  
32    /**
33     * After application ends.
34     */
35    void postApplication();
36  
37    /**
38     * If there is an error during the application.
39     *
40     * @param e Exception that caused failure. May be null.
41     */
42    void applicationFailed(Exception e);
43  
44    /**
45     * Before each superstep starts.
46     *
47     * @param superstep The superstep number
48     */
49    void preSuperstep(long superstep);
50  
51    /**
52     * After each superstep ends.
53     *
54     * @param superstep The superstep number
55     */
56    void postSuperstep(long superstep);
57  }