| /** |
| * 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 example; |
| |
| import java.io.IOException; |
| import java.util.*; |
| |
| import org.apache.avro.Schema; |
| import org.apache.avro.Schema.Type; |
| import org.apache.avro.mapred.AvroWrapper; |
| import org.apache.avro.mapred.Pair; |
| import org.apache.avro.mapreduce.AvroJob; |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.hadoop.conf.Configured; |
| import org.apache.hadoop.fs.Path; |
| import org.apache.hadoop.io.IntWritable; |
| import org.apache.hadoop.io.LongWritable; |
| import org.apache.hadoop.io.NullWritable; |
| import org.apache.hadoop.io.Text; |
| import org.apache.hadoop.mapreduce.Job; |
| import org.apache.hadoop.mapreduce.Mapper; |
| import org.apache.hadoop.mapreduce.Reducer; |
| import org.apache.hadoop.mapreduce.lib.input.FileInputFormat; |
| import org.apache.hadoop.mapreduce.lib.input.TextInputFormat; |
| import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat; |
| import org.apache.hadoop.util.Tool; |
| import org.apache.hadoop.util.ToolRunner; |
| |
| /** |
| * The classic WordCount example modified to output Avro Pair<CharSequence, |
| * Integer> records instead of text. |
| */ |
| public class MapReduceAvroWordCount extends Configured implements Tool { |
| |
| public static class Map |
| extends Mapper<LongWritable, Text, Text, IntWritable> { |
| |
| private final static IntWritable one = new IntWritable(1); |
| private Text word = new Text(); |
| |
| public void map(LongWritable key, Text value, Context context) |
| throws IOException, InterruptedException { |
| String line = value.toString(); |
| StringTokenizer tokenizer = new StringTokenizer(line); |
| while (tokenizer.hasMoreTokens()) { |
| word.set(tokenizer.nextToken()); |
| context.write(word, one); |
| } |
| } |
| } |
| |
| public static class Reduce |
| extends Reducer<Text, IntWritable, |
| AvroWrapper<Pair<CharSequence, Integer>>, NullWritable> { |
| |
| public void reduce(Text key, Iterable<IntWritable> values, |
| Context context) |
| throws IOException, InterruptedException { |
| int sum = 0; |
| for (IntWritable value : values) { |
| sum += value.get(); |
| } |
| context.write(new AvroWrapper<Pair<CharSequence, Integer>> |
| (new Pair<CharSequence, Integer>(key.toString(), sum)), |
| NullWritable.get()); |
| } |
| } |
| |
| public int run(String[] args) throws Exception { |
| if (args.length != 2) { |
| System.err.println("Usage: AvroWordCount <input path> <output path>"); |
| return -1; |
| } |
| |
| Job job = new Job(getConf()); |
| job.setJarByClass(MapReduceAvroWordCount.class); |
| job.setJobName("wordcount"); |
| |
| // We call setOutputSchema first so we can override the configuration |
| // parameters it sets |
| AvroJob.setOutputKeySchema(job, |
| Pair.getPairSchema(Schema.create(Type.STRING), |
| Schema.create(Type.INT))); |
| job.setOutputValueClass(NullWritable.class); |
| |
| job.setMapperClass(Map.class); |
| job.setReducerClass(Reduce.class); |
| |
| job.setInputFormatClass(TextInputFormat.class); |
| |
| job.setMapOutputKeyClass(Text.class); |
| job.setMapOutputValueClass(IntWritable.class); |
| job.setSortComparatorClass(Text.Comparator.class); |
| |
| FileInputFormat.setInputPaths(job, new Path(args[0])); |
| FileOutputFormat.setOutputPath(job, new Path(args[1])); |
| |
| job.waitForCompletion(true); |
| |
| return 0; |
| } |
| |
| public static void main(String[] args) throws Exception { |
| int res = |
| ToolRunner.run(new Configuration(), new MapReduceAvroWordCount(), args); |
| System.exit(res); |
| } |
| } |