Source code

001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *   http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019package org.apache.reef.vortex.api;
020
021import org.apache.reef.annotations.Unstable;
022import org.apache.reef.annotations.audience.ClientSide;
023import org.apache.reef.annotations.audience.Public;
024import org.apache.reef.io.serialization.Codec;
025
026import java.io.Serializable;
027import java.util.List;
028
029/**
030 * Typed user function for Local Aggregation. Implement your functions using this interface.
031 * TODO[REEF-504]: Clean up Serializable in Vortex.
032 * TODO[REEF-1003]: Use reflection instead of serialization when launching VortexFunction.
033 *
034 * @param <TOutput> output type of the aggregation function and the functions to-be-aggregated.
035 */
036@Public
037@ClientSide
038@Unstable
039public interface VortexAggregateFunction<TOutput> extends Serializable {
040
041  /**
042   * Runs a custom local aggregation function on Tasklets assigned to a VortexWorker.
043   * @param taskletOutputs the list of outputs from Tasklets on a Worker.
044   * @return the aggregated output of Tasklets.
045   * @throws Exception
046   */
047  TOutput call(final List<TOutput> taskletOutputs) throws VortexAggregateException;
048
049  /**
050   * Users must define codec for the AggregationOutput.
051   * {@link org.apache.reef.vortex.util.VoidCodec} can be used if the aggregation output is
052   * empty, and {@link org.apache.reef.io.serialization.SerializableCodec} can be used for ({@link Serializable}
053   * aggregation output.
054   * Custom aggregation output Codec can also be supplied.
055   * @return Codec used to serialize/deserialize the output.
056   */
057  Codec<TOutput> getOutputCodec();
058}