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.util.Optional; 025 026import java.util.Collections; 027import java.util.List; 028 029/** 030 * The result of an aggregate. Registered to callbacks for {@link VortexAggregateFuture}. 031 */ 032@Public 033@ClientSide 034@Unstable 035public final class AggregateResult<TInput, TOutput> { 036 037 private final Optional<TOutput> aggregatedOutput; 038 private final List<TInput> inputList; 039 private final Optional<Exception> exception; 040 041 AggregateResult(final Exception exception, 042 final List<TInput> inputList) { 043 this(Optional.<TOutput>empty(), Optional.of(exception), inputList); 044 } 045 046 AggregateResult(final TOutput aggregatedOutput, 047 final List<TInput> inputList) { 048 this(Optional.of(aggregatedOutput), Optional.<Exception>empty(), inputList); 049 } 050 051 private AggregateResult(final Optional<TOutput> aggregatedOutput, 052 final Optional<Exception> exception, 053 final List<TInput> inputList) { 054 this.aggregatedOutput = aggregatedOutput; 055 this.inputList = Collections.unmodifiableList(inputList); 056 this.exception = exception; 057 } 058 059 /** 060 * @return the output of an aggregation, throws the Exception if a Tasklet or an aggregation fails. 061 * If an aggregation fails, {@link VortexAggregateException} will be thrown, otherwise 062 * the Exception that caused the Tasklet to fail will be thrown directly. 063 * @throws Exception the Exception that caused the Tasklet or aggregation failure. 064 */ 065 public TOutput getAggregateResult() throws VortexAggregateException { 066 if (exception.isPresent()) { 067 throw new VortexAggregateException(exception.get(), inputList); 068 } 069 070 return aggregatedOutput.get(); 071 } 072 073 /** 074 * @return the associated inputs of an aggregation 075 */ 076 public List<TInput> getAggregatedInputs() { 077 return inputList; 078 } 079 080 /** 081 * If an aggregation fails, {@link VortexAggregateException} will be thrown, otherwise 082 * the Exception that caused the Tasklet to fail will be thrown directly. 083 * @return the Exception that caused the Tasklet or aggregation failure, if any. 084 */ 085 public Optional<Exception> getException() { 086 return exception; 087 } 088}