1/*2 * Licensed to the Apache Software Foundation (ASF) under one3 * or more contributor license agreements. See the NOTICE file4 * distributed with this work for additional information5 * regarding copyright ownership. The ASF licenses this file6 * to you under the Apache License, Version 2.0 (the7 * "License"); you may not use this file except in compliance8 * with the License. You may obtain a copy of the License at9 *10 * http://www.apache.org/licenses/LICENSE-2.011 *12 * Unless required by applicable law or agreed to in writing, software13 * 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 and16 * limitations under the License.17 */18package org.apache.giraph.examples;
1920import org.apache.giraph.graph.BasicComputation;
21import org.apache.giraph.graph.Vertex;
22import org.apache.hadoop.io.IntWritable;
23import org.apache.hadoop.io.NullWritable;
2425import java.io.IOException;
2627/**28 * Simple algorithm that computes the max value in the graph.29 */30publicclassMaxComputationextends BasicComputation<IntWritable, IntWritable,
31 NullWritable, IntWritable> {
32 @Override
33publicvoid compute(Vertex<IntWritable, IntWritable, NullWritable> vertex,
34 Iterable<IntWritable> messages) throws IOException {
35boolean changed = false;
36for (IntWritable message : messages) {
37if (vertex.getValue().get() < message.get()) {
38 vertex.setValue(message);
39 changed = true;
40 }
41 }
42if (getSuperstep() == 0 || changed) {
43 sendMessageToAllEdges(vertex, vertex.getValue());
44 }
45 vertex.voteToHalt();
46 }
47 }