/*

  * 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.giraph.bsp.checkpoints;

 import org.apache.giraph.conf.GiraphConfiguration;

 import org.apache.giraph.master.MasterCompute;

 /**

  * To prevent accidental checkpointing of non-checkpointable app

  * you may provide implementation of this interface. Most apps are

  * checkpointable by default, however some apps are not checkpointable,

  * e.g. apps that use static variables to pass data around between supersteps

  * or start new threads or use external resources. This interface allows

  * you to specify if and when your app is checkpointable.

  */

 public interface CheckpointSupportedChecker {

   /**

    * Does the job support checkpoints?

    * It is true by default, set it to false if your job uses some

    * non-checkpointable features:

    * - static variables for storing data between supersteps.

    * - starts new threads or uses Timers

    * - writes output before job is complete, etc

    * This method is called on master and has access to

    * job configuration and master compute.

    *

    * @param conf giraph configuration

    * @param masterCompute instance of master compute

    * @return true if checkpointing on current superstep is supported

    * by this application.

    */

   boolean isCheckpointSupported(GiraphConfiguration conf,

                                        MasterCompute masterCompute);

 }