Java tutorial
/** * 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.tez.mapreduce.examples; import java.io.IOException; import java.util.StringTokenizer; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.Path; import org.apache.hadoop.io.IntWritable; import org.apache.hadoop.io.Text; import org.apache.hadoop.mapreduce.Job; import org.apache.hadoop.mapreduce.JobID; import org.apache.hadoop.mapreduce.Mapper; import org.apache.hadoop.mapreduce.Reducer; import org.apache.hadoop.mapreduce.TypeConverter; import org.apache.hadoop.mapreduce.lib.input.FileInputFormat; import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat; import org.apache.hadoop.util.GenericOptionsParser; import org.apache.hadoop.yarn.api.records.ApplicationId; import org.apache.hadoop.yarn.client.api.YarnClient; import org.apache.hadoop.yarn.client.api.impl.YarnClientImpl; import org.apache.tez.client.TezClient; import org.apache.tez.dag.api.TezConfiguration; import org.apache.tez.dag.api.TezException; import org.apache.tez.dag.api.client.DAGClient; import org.apache.tez.dag.api.client.DAGStatus; import org.apache.tez.mapreduce.hadoop.MRJobConfig; import org.apache.tez.mapreduce.hadoop.MultiStageMRConfigUtil; /** * An MRR job built on top of word count to return words sorted by * their frequency of occurrence. */ public class OrderedWordCount { private static Log LOG = LogFactory.getLog(OrderedWordCount.class); public static class TokenizerMapper extends Mapper<Object, Text, Text, IntWritable> { private final static IntWritable one = new IntWritable(1); private Text word = new Text(); public void map(Object key, Text value, Context context) throws IOException, InterruptedException { StringTokenizer itr = new StringTokenizer(value.toString()); while (itr.hasMoreTokens()) { word.set(itr.nextToken()); context.write(word, one); } } } public static class IntSumReducer extends Reducer<Text, IntWritable, IntWritable, Text> { private IntWritable result = new IntWritable(); public void reduce(Text key, Iterable<IntWritable> values, Context context) throws IOException, InterruptedException { int sum = 0; for (IntWritable val : values) { sum += val.get(); } result.set(sum); context.write(result, key); } } /** * Shuffle ensures ordering based on count of employees per department * hence the final reducer is a no-op and just emits the department name * with the employee count per department. */ public static class MyOrderByNoOpReducer extends Reducer<IntWritable, Text, Text, IntWritable> { public void reduce(IntWritable key, Iterable<Text> values, Context context) throws IOException, InterruptedException { for (Text word : values) { context.write(word, key); } } } public static void main(String[] args) throws Exception { Configuration conf = new Configuration(); String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs(); if (otherArgs.length != 2) { System.err.println("Usage: wordcount <in> <out>"); System.exit(2); } // Configure intermediate reduces conf.setInt(MRJobConfig.MRR_INTERMEDIATE_STAGES, 1); // Set reducer class for intermediate reduce conf.setClass(MultiStageMRConfigUtil.getPropertyNameForIntermediateStage(1, "mapreduce.job.reduce.class"), IntSumReducer.class, Reducer.class); // Set reducer output key class conf.setClass( MultiStageMRConfigUtil.getPropertyNameForIntermediateStage(1, "mapreduce.map.output.key.class"), IntWritable.class, Object.class); // Set reducer output value class conf.setClass( MultiStageMRConfigUtil.getPropertyNameForIntermediateStage(1, "mapreduce.map.output.value.class"), Text.class, Object.class); conf.setInt(MultiStageMRConfigUtil.getPropertyNameForIntermediateStage(1, "mapreduce.job.reduces"), 2); @SuppressWarnings("deprecation") Job job = new Job(conf, "orderedwordcount"); job.setJarByClass(OrderedWordCount.class); // Configure map job.setMapperClass(TokenizerMapper.class); job.setMapOutputKeyClass(Text.class); job.setMapOutputValueClass(IntWritable.class); // Configure reduce job.setReducerClass(MyOrderByNoOpReducer.class); job.setOutputKeyClass(Text.class); job.setOutputValueClass(IntWritable.class); FileInputFormat.addInputPath(job, new Path(otherArgs[0])); FileOutputFormat.setOutputPath(job, new Path(otherArgs[1])); YarnClient yarnClient = new YarnClientImpl(); yarnClient.init(conf); yarnClient.start(); TezClient tezClient = new TezClient(new TezConfiguration(conf)); job.submit(); JobID jobId = job.getJobID(); ApplicationId appId = TypeConverter.toYarn(jobId).getAppId(); DAGClient dagClient = tezClient.getDAGClient(appId); DAGStatus dagStatus = null; while (true) { dagStatus = dagClient.getDAGStatus(); if (dagStatus.getState() == DAGStatus.State.RUNNING || dagStatus.getState() == DAGStatus.State.SUCCEEDED || dagStatus.getState() == DAGStatus.State.FAILED || dagStatus.getState() == DAGStatus.State.KILLED || dagStatus.getState() == DAGStatus.State.ERROR) { break; } try { Thread.sleep(500); } catch (InterruptedException e) { // continue; } } while (dagStatus.getState() == DAGStatus.State.RUNNING) { try { ExampleDriver.printMRRDAGStatus(dagStatus); try { Thread.sleep(1000); } catch (InterruptedException e) { // continue; } dagStatus = dagClient.getDAGStatus(); } catch (TezException e) { LOG.fatal("Failed to get application progress. Exiting"); System.exit(-1); } } ExampleDriver.printMRRDAGStatus(dagStatus); LOG.info("Application completed. " + "FinalState=" + dagStatus.getState()); System.exit(dagStatus.getState() == DAGStatus.State.SUCCEEDED ? 0 : 1); } }