| /* |
| * 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.nemo.compiler.frontend.beam.transform; |
| |
| import org.apache.beam.sdk.coders.CannotProvideCoderException; |
| import org.apache.beam.sdk.coders.Coder; |
| import org.apache.beam.sdk.coders.CoderRegistry; |
| import org.apache.beam.sdk.transforms.Combine; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * Wrapper class for {@link Combine.CombineFn}. |
| * When invoked to output, it outputs its accumulator, instead of the output from its original combine function. |
| * @param <InputT> input type |
| * @param <AccumT> accumulator type |
| */ |
| public final class PartialCombineFn<InputT, AccumT> extends Combine.CombineFn<InputT, AccumT, AccumT> { |
| private static final Logger LOG = LoggerFactory.getLogger(PartialCombineFn.class.getName()); |
| private final Combine.CombineFn<InputT, AccumT, ?> originFn; |
| private final Coder<AccumT> accumCoder; |
| |
| public PartialCombineFn(final Combine.CombineFn<InputT, AccumT, ?> originFn, |
| final Coder<AccumT> accumCoder) { |
| this.originFn = originFn; |
| this.accumCoder = accumCoder; |
| } |
| |
| @Override |
| public AccumT createAccumulator() { |
| return originFn.createAccumulator(); |
| } |
| |
| @Override |
| public AccumT addInput(final AccumT accumulator, final InputT input) { |
| return originFn.addInput(accumulator, input); |
| } |
| |
| @Override |
| public AccumT mergeAccumulators(final Iterable<AccumT> accumulators) { |
| return originFn.mergeAccumulators(accumulators); |
| } |
| |
| @Override |
| public AccumT extractOutput(final AccumT accumulator) { |
| return accumulator; |
| } |
| |
| @Override |
| public Coder<AccumT> getAccumulatorCoder(final CoderRegistry registry, final Coder<InputT> inputCoder) |
| throws CannotProvideCoderException { |
| return accumCoder; |
| } |
| } |