/*

  * 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.comm.aggregators;

 import java.io.IOException;

 import org.apache.hadoop.io.Writable;

 /**

  * Aggregates worker aggregator requests and sends them off

  */

 public interface WorkerAggregatorRequestProcessor {

   /**

    * Sends worker reduced value to the owner of reducer

    *

    * @param name Name of the reducer

    * @param reducedValue Reduced partial value

    * @throws java.io.IOException

    * @return True if reduced value will be sent, false if this worker is

    * the owner of the reducer

    */

   boolean sendReducedValue(String name,

       Writable reducedValue) throws IOException;

   /**

    * Flush aggregated values cache.

    *

    * @throws IOException

    */

   void flush() throws IOException;

   /**

    * Sends reduced values to the master. This worker is the owner of these

    * reducers.

    *

    * @param data Serialized reduced values data

    * @throws IOException

    */

   void sendReducedValuesToMaster(byte[] data) throws IOException;

   /**

    * Sends reduced values to all other workers

    *

    * @param reducedDataList Serialized reduced values data split into chunks

    */

   void distributeReducedValues(

       Iterable<byte[]> reducedDataList) throws IOException;

 }