1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one 3 * or more contributor license agreements. See the NOTICE file 4 * distributed with this work for additional information 5 * regarding copyright ownership. The ASF licenses this file 6 * to you under the Apache License, Version 2.0 (the 7 * "License"); you may not use this file except in compliance 8 * with the License. You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 */ 18 package org.apache.giraph.block_app.reducers.collect; 19 20 import java.util.ArrayList; 21 import java.util.List; 22 23 import org.apache.giraph.reducers.impl.KryoWrappedReduceOperation; 24 25 /** 26 * Collect values reduce operation 27 * 28 * @param <S> Type of values to collect 29 */ 30 public class CollectReduceOperation<S> 31 extends KryoWrappedReduceOperation<S, List<S>> { 32 @Override 33 public List<S> createValue() { 34 return createList(); 35 } 36 37 @Override 38 public void reduce(List<S> reduceInto, S value) { 39 reduceInto.add(value); 40 } 41 42 @Override 43 public void reduceMerge(List<S> reduceInto, List<S> toReduce) { 44 reduceInto.addAll(toReduce); 45 } 46 47 public List<S> createList() { 48 return new ArrayList<>(); 49 } 50 }