/*

  * 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.master;

 import java.io.DataInput;

 import java.io.DataOutput;

 import java.io.IOException;

 import org.apache.giraph.aggregators.Aggregator;

 import org.apache.giraph.conf.DefaultImmutableClassesGiraphConfigurable;

 import org.apache.giraph.utils.ReflectionUtils;

 import org.apache.giraph.utils.WritableUtils;

 import org.apache.hadoop.io.Writable;

 /**

  * Writable representation of aggregated value

  *

  * @param <A> Aggregation object type

  */

 public class AggregatorBroadcast<A extends Writable>

   extends DefaultImmutableClassesGiraphConfigurable

   implements Writable {

   /** Aggregator class */

   private Class<? extends Aggregator<A>> aggregatorClass;

   /** Aggregated value */

   private A value;

   /** Constructor */

   public AggregatorBroadcast() {

   }

   /**

    * Constructor

    * @param aggregatorClass Aggregator class

    * @param value Aggregated value

    */

   public AggregatorBroadcast(

       Class<? extends Aggregator<A>> aggregatorClass, A value) {

     this.aggregatorClass = aggregatorClass;

     this.value = value;

   }

   public A getValue() {

     return value;

   }

   @Override

   public void write(DataOutput out) throws IOException {

     WritableUtils.writeClass(aggregatorClass, out);

     value.write(out);

   }

   @Override

   public void readFields(DataInput in) throws IOException {

     aggregatorClass = WritableUtils.readClass(in);

     value = ReflectionUtils.newInstance(aggregatorClass, getConf())

         .createInitialValue();

     value.readFields(in);

   }

 }