/*

  * 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.examples.block_app;

 import java.io.IOException;

 import org.apache.giraph.aggregators.DoubleOverwriteAggregator;

 import org.apache.giraph.block_app.framework.block.Block;

 import org.apache.giraph.block_app.migration.MigrationAbstractComputation.MigrationFullBasicComputation;

 import org.apache.giraph.block_app.migration.MigrationFullBlockFactory;

 import org.apache.giraph.block_app.migration.MigrationMasterCompute.MigrationFullMasterCompute;

 import org.apache.giraph.block_app.migration.MigrationWorkerContext.MigrationFullWorkerContext;

 import org.apache.giraph.conf.GiraphConfiguration;

 import org.apache.giraph.graph.Vertex;

 import org.apache.hadoop.io.DoubleWritable;

 import org.apache.hadoop.io.FloatWritable;

 import org.apache.hadoop.io.LongWritable;

 import org.apache.log4j.Logger;

 /**

  * Demonstrates using migration library for Blocks Framework,

  * as an drop-in replacement, without any changes.

  */

 public class SimpleMigrationMasterBlockFactory

     extends MigrationFullBlockFactory {

   @Override

   public Block createBlock(GiraphConfiguration conf) {

     return createMigrationAppBlock(

         SimpleMigrationMasterComputation.class,

         new SimpleMigrationMasterCompute(),

         DoubleWritable.class,

         null,

         conf);

   }

   @Override

   protected Class<LongWritable> getVertexIDClass(GiraphConfiguration conf) {

     return LongWritable.class;

   }

   @Override

   protected Class<DoubleWritable> getVertexValueClass(

       GiraphConfiguration conf) {

     return DoubleWritable.class;

   }

   @Override

   protected Class<FloatWritable> getEdgeValueClass(GiraphConfiguration conf) {

     return FloatWritable.class;

   }

   @Override

   protected

   Class<SimpleMigrationMasterWorkerContext> getWorkerContextValueClass(

       GiraphConfiguration conf) {

     return SimpleMigrationMasterWorkerContext.class;

   }

   // Full copy from org.apache.giraph.examples.SimpleMasterComputeComputation

   // Just extending MigrationFull drop-in replacements instead.

   /**

    * Demonstrates a computation with a centralized part implemented via a

    * MasterCompute.

    */

   public static class SimpleMigrationMasterComputation

       extends MigrationFullBasicComputation<LongWritable, DoubleWritable,

       FloatWritable, DoubleWritable> {

     /** Aggregator to get values from the master to the workers */

     public static final String SMC_AGG = "simplemastercompute.aggregator";

     /** Logger */

     private static final Logger LOG =

         Logger.getLogger(SimpleMigrationMasterComputation.class);

     @Override

     public void compute(

         Vertex<LongWritable, DoubleWritable, FloatWritable> vertex,

         Iterable<DoubleWritable> messages) throws IOException {

       double oldSum = getSuperstep() == 0 ? 0 : vertex.getValue().get();

       double newValue = this.<DoubleWritable>getAggregatedValue(SMC_AGG).get();

       double newSum = oldSum + newValue;

       vertex.setValue(new DoubleWritable(newSum));

       SimpleMigrationMasterWorkerContext workerContext = getWorkerContext();

       workerContext.setFinalSum(newSum);

       LOG.info("Current sum: " + newSum);

     }

   }

   /**

    * Worker context used with {@link SimpleMigrationMasterComputation}.

    */

   public static class SimpleMigrationMasterWorkerContext

       extends MigrationFullWorkerContext {

     /** Final sum value for verification for local jobs */

     private static double FINAL_SUM;

     @Override

     public void preApplication()

       throws InstantiationException, IllegalAccessException {

     }

     @Override

     public void preSuperstep() {

     }

     @Override

     public void postSuperstep() {

     }

     @Override

     public void postApplication() {

     }

     public static void setFinalSum(double sum) {

       FINAL_SUM = sum;

     }

     public static double getFinalSum() {

       return FINAL_SUM;

     }

   }

   /**

    * MasterCompute used with {@link SimpleMigrationMasterComputation}.

    */

   public static class SimpleMigrationMasterCompute

       extends MigrationFullMasterCompute {

     @Override

     public void compute() {

       setAggregatedValue(SimpleMigrationMasterComputation.SMC_AGG,

           new DoubleWritable(((double) getSuperstep()) / 2 + 1));

       if (getSuperstep() == 10) {

         haltComputation();

       }

     }

     @Override

     public void initialize() throws InstantiationException,

         IllegalAccessException {

       registerAggregator(SimpleMigrationMasterComputation.SMC_AGG,

           DoubleOverwriteAggregator.class);

     }

   }

 }