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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  import org.apache.giraph.metrics.AggregatedMetrics;
23  import org.apache.giraph.partition.PartitionStats;
24  
25  import java.util.List;
26  
27  /**
28   * Observer for Master.
29   * It can implement ContextSettable if it needs to access job counters.
30   */
31  public interface MasterObserver extends ImmutableClassesGiraphConfigurable {
32    /**
33     * Before application begins.
34     */
35    void preApplication();
36  
37    /**
38     * After application ends.
39     */
40    void postApplication();
41  
42    /**
43     * If there is an error during the application.
44     *
45     * @param e Exception that caused failure. May be null.
46     */
47    void applicationFailed(Exception e);
48  
49    /**
50     * Before each superstep starts.
51     *
52     * @param superstep The superstep number
53     */
54    void preSuperstep(long superstep);
55  
56    /**
57     * After each superstep ends.
58     *
59     * @param superstep The superstep number
60     */
61    void postSuperstep(long superstep);
62  
63    /**
64     * Called after each superstep with aggregated metrics from workers
65     *
66     * @param superstep Supsertep number
67     * @param aggregatedMetrics Metrics
68     * @param partitionStatsList List of partition stats
69     */
70    void superstepMetricsUpdate(
71        long superstep, AggregatedMetrics aggregatedMetrics,
72        List<PartitionStats> partitionStatsList);
73  }