/*

  * 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;

 import org.apache.giraph.graph.BasicComputation;

 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;

 import java.io.IOException;

 /**

  * Vertex to allow unit testing of failure detection

  */

 public class SimpleFailComputation extends BasicComputation<

     LongWritable, DoubleWritable, FloatWritable, DoubleWritable> {

   /** Class logger */

   private static Logger LOG = Logger.getLogger(SimpleFailComputation.class);

   /** TODO: Change this behavior to WorkerContext */

   private static long SUPERSTEP = 0;

   @Override

   public void compute(

       Vertex<LongWritable, DoubleWritable, FloatWritable> vertex,

       Iterable<DoubleWritable> messages) throws IOException {

     if (getSuperstep() >= 1) {

       double sum = 0;

       for (DoubleWritable message : messages) {

         sum += message.get();

       }

       DoubleWritable vertexValue =

           new DoubleWritable((0.15f / getTotalNumVertices()) + 0.85f * sum);

       vertex.setValue(vertexValue);

       if (getSuperstep() < 30) {

         if (getSuperstep() == 20) {

           if (vertex.getId().get() == 10L) {

             try {

               Thread.sleep(2000);

             } catch (InterruptedException e) {

               LOG.info("Sleep interrupted ", e);

             }

             System.exit(1);

           } else if (getSuperstep() - SUPERSTEP > 10) {

             return;

           }

         }

         long edges = vertex.getNumEdges();

         sendMessageToAllEdges(vertex,

             new DoubleWritable(vertex.getValue().get() / edges));

       } else {

         vertex.voteToHalt();

       }

       setSuperstep(getSuperstep());

     }

   }

   /**

    * Set the superstep

    *

    * @param superstep to set

    */

   private static void setSuperstep(long superstep) {

     SUPERSTEP = superstep;

   }

 }