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 19 package org.apache.giraph.aggregators.matrix; 20 21 import java.util.ArrayList; 22 23 /** 24 * The abstract matrix aggregator contains the prefix name of the vector 25 * aggregators that have the values of the rows. It also cashes the names to 26 * avoid creating the same string multiples times. 27 */ 28 public abstract class MatrixSumAggregator { 29 /** 30 * The prefix name of the vector aggregators. The aggregator names are created 31 * as (name0, name1, ...). 32 */ 33 private String name; 34 /** Cache the names of the columns */ 35 private ArrayList<String> names = new ArrayList<>(); 36 37 /** 38 * Create a new matrix aggregator with the given prefix name for the vector 39 * aggregators. 40 * 41 * @param name the prefix for the row vector aggregators 42 */ 43 public MatrixSumAggregator(String name) { 44 this.name = name; 45 } 46 47 /** 48 * Get the name of the aggreagator of the row with the index specified. 49 * 50 * @param i the row of the matrix 51 * @return the name of the aggregator 52 */ 53 protected String getRowAggregatorName(int i) { 54 for (int n = names.size(); n <= i; ++n) { 55 names.add(name + n); 56 } 57 return names.get(i); 58 } 59 }