| /* |
| * 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.spark.transform; |
| |
| import org.apache.nemo.common.ir.OutputCollector; |
| import org.apache.nemo.common.ir.vertex.transform.Transform; |
| import org.apache.nemo.common.punctuation.Watermark; |
| import org.apache.spark.api.java.function.PairFunction; |
| import scala.Tuple2; |
| |
| /** |
| * Map elements to Pair elements. |
| * |
| * @param <T> input type. |
| * @param <K> output key type. |
| * @param <V> output value type. |
| */ |
| public final class MapToPairTransform<T, K, V> implements Transform<T, Tuple2<K, V>> { |
| private final PairFunction<T, K, V> func; |
| private OutputCollector<Tuple2<K, V>> outputCollector; |
| |
| /** |
| * Constructor. |
| * |
| * @param func Pair function to apply to each element. |
| */ |
| public MapToPairTransform(final PairFunction<T, K, V> func) { |
| this.func = func; |
| } |
| |
| @Override |
| public void prepare(final Context context, final OutputCollector<Tuple2<K, V>> oc) { |
| this.outputCollector = oc; |
| } |
| |
| @Override |
| public void onData(final T element) { |
| try { |
| Tuple2<K, V> data = func.call(element); |
| outputCollector.emit(data); |
| } catch (Exception e) { |
| throw new RuntimeException(e); |
| } |
| } |
| |
| @Override |
| public void onWatermark(final Watermark watermark) { |
| outputCollector.emitWatermark(watermark); |
| } |
| |
| @Override |
| public void close() { |
| // Nothing to do in a SparkTransform. |
| } |
| } |