| /* |
| * 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 org.apache.giraph.reducers.ReduceOperation; |
| import org.apache.hadoop.io.Writable; |
| |
| /** |
| * Master compute can access reduce and broadcast methods |
| * through this interface, from masterCompute method. |
| */ |
| public interface MasterGlobalCommUsageAggregators { |
| /** |
| * Register reducer to be reduced in the next worker computation, |
| * using given name and operations. |
| * @param name Name of the reducer |
| * @param reduceOp Reduce operations |
| * @param <S> Single value type |
| * @param <R> Reduced value type |
| */ |
| <S, R extends Writable> void registerReducer( |
| String name, ReduceOperation<S, R> reduceOp); |
| |
| /** |
| * Register reducer to be reduced in the next worker computation, using |
| * given name and operations, starting globally from globalInitialValue. |
| * (globalInitialValue is reduced only once, each worker will still start |
| * from neutral initial value) |
| * |
| * @param name Name of the reducer |
| * @param reduceOp Reduce operations |
| * @param globalInitialValue Global initial value |
| * @param <S> Single value type |
| * @param <R> Reduced value type |
| */ |
| <S, R extends Writable> void registerReducer( |
| String name, ReduceOperation<S, R> reduceOp, R globalInitialValue); |
| |
| /** |
| * Get reduced value from previous worker computation. |
| * @param name Name of the reducer |
| * @return Reduced value |
| * @param <R> Reduced value type |
| */ |
| <R extends Writable> R getReduced(String name); |
| |
| /** |
| * Broadcast given value to all workers for next computation. |
| * @param name Name of the broadcast object |
| * @param value Value |
| */ |
| void broadcast(String name, Writable value); |
| } |