Example usage for org.apache.hadoop.mapreduce.lib.chain ChainReducer addMapper

Introduction

In this page you can find the example usage for org.apache.hadoop.mapreduce.lib.chain ChainReducer addMapper.

Prototype

public static void addMapper(Job job, Class<? extends Mapper> klass, Class<?> inputKeyClass,
        Class<?> inputValueClass, Class<?> outputKeyClass, Class<?> outputValueClass, Configuration mapperConf)
        throws IOException 

Source Link

Document

Adds a Mapper class to the chain reducer.

Usage

From source file:njit.cs698.wenbin.WordCount.java

License:Apache License

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> [<in>...] <out>");
        System.exit(2);/*from   w ww. ja  v  a  2  s  .c  o  m*/
    }
    Job job = Job.getInstance(conf, "word count");
    job.setJarByClass(WordCount.class);
    job.setMapperClass(TokenizerMapper.class);
    job.setCombinerClass(IntSumReducer.class);
    job.setMapOutputKeyClass(Text.class);
    job.setMapOutputValueClass(IntWritable.class);
    //job.setReducerClass(IntSumReducer.class);
    ChainReducer.setReducer(job, IntSumReducer.class, Text.class, IntWritable.class, Text.class,
            IntWritable.class, new Configuration(false));
    ChainReducer.addMapper(job, ReducerMapper.class, Text.class, IntWritable.class, IntWritable.class,
            Text.class, new Configuration(false));
    //job.setOutputKeyClass(Text.class);
    //job.setOutputValueClass(IntWritable.class);
    for (int i = 0; i < otherArgs.length - 1; ++i) {
        FileInputFormat.addInputPath(job, new Path(otherArgs[i]));
    }
    FileOutputFormat.setOutputPath(job, new Path(otherArgs[otherArgs.length - 1]));
    System.exit(job.waitForCompletion(true) ? 0 : 1);
}

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