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.partition; 19 20 import org.apache.hadoop.io.Writable; 21 import org.apache.hadoop.io.WritableComparable; 22 23 /** 24 * Divides the vertices into partitions by their hash code using a simple 25 * round-robin hash for great balancing if given a random hash code. 26 * 27 * @param <I> Vertex id value 28 * @param <V> Vertex value 29 * @param <E> Edge value 30 */ 31 public class HashPartitionerFactory<I extends WritableComparable, 32 V extends Writable, E extends Writable> 33 extends GraphPartitionerFactory<I, V, E> { 34 35 @Override 36 public int getPartition(I id, int partitionCount, int workerCount) { 37 return Math.abs(id.hashCode() % partitionCount); 38 } 39 40 @Override 41 public int getWorker(int partition, int partitionCount, int workerCount) { 42 return partition % workerCount; 43 } 44 }