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CheckpointSupportedChecker xref
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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  package org.apache.giraph.bsp.checkpoints;
19  
20  import org.apache.giraph.conf.GiraphConfiguration;
21  import org.apache.giraph.master.MasterCompute;
22  
23  /**
24   * To prevent accidental checkpointing of non-checkpointable app
25   * you may provide implementation of this interface. Most apps are
26   * checkpointable by default, however some apps are not checkpointable,
27   * e.g. apps that use static variables to pass data around between supersteps
28   * or start new threads or use external resources. This interface allows
29   * you to specify if and when your app is checkpointable.
30   */
31  public interface CheckpointSupportedChecker {
32  
33    /**
34     * Does the job support checkpoints?
35     * It is true by default, set it to false if your job uses some
36     * non-checkpointable features:
37     * - static variables for storing data between supersteps.
38     * - starts new threads or uses Timers
39     * - writes output before job is complete, etc
40     * This method is called on master and has access to
41     * job configuration and master compute.
42     *
43     * @param conf giraph configuration
44     * @param masterCompute instance of master compute
45     * @return true if checkpointing on current superstep is supported
46     * by this application.
47     */
48    boolean isCheckpointSupported(GiraphConfiguration conf,
49                                         MasterCompute masterCompute);
50  
51  }