mapreduce program using hcatalog to write output

gistfile1.txt

public class WriteRC extends Configured implements Tool {

    public static class Map extends
            Mapper<WritableComparable, HCatRecord, WritableComparable, HCatRecord> {

        String name;
        Integer age;
        Double gpa;

        @Override
        protected void map(
                WritableComparable key,
                HCatRecord value,
                org.apache.hadoop.mapreduce.Mapper<WritableComparable, HCatRecord, WritableComparable, HCatRecord>.Context context)
                throws IOException, InterruptedException {
            name = value.get(0)==null?null:(String)value.get(0);
            age = value.get(1)==null?null:(Integer)value.get(1);
            gpa = value.get(2)==null?null:(Double)value.get(2);

            if (gpa != null) gpa = Math.floor(gpa) + 0.1;

            HCatRecord record = new DefaultHCatRecord(5);
            record.set(0, name);
            record.set(1, age);
            record.set(2, gpa);
            
            context.write(null, record);

        }
    }

    public int run(String[] args) throws Exception {
        Configuration conf = getConf();
        args = new GenericOptionsParser(conf, args).getRemainingArgs();

        String serverUri = args[0];
        String inputTableName = args[1];
        String outputTableName = args[2];
        String dbName = null;

        String principalID = System
                .getProperty(HCatConstants.HCAT_METASTORE_PRINCIPAL);
        if (principalID != null)
            conf.set(HCatConstants.HCAT_METASTORE_PRINCIPAL, principalID);
        Job job = new Job(conf, "WriteRC");
        HCatInputFormat.setInput(job, InputJobInfo.create(dbName,
                inputTableName, null, null));
        // initialize HCatOutputFormat

        job.setInputFormatClass(HCatInputFormat.class);
        job.setJarByClass(WriteRC.class);
        job.setMapperClass(Map.class);
        job.setOutputKeyClass(WritableComparable.class);
        job.setOutputValueClass(DefaultHCatRecord.class);
        job.setNumReduceTasks(0);
        HCatOutputFormat.setOutput(job, OutputJobInfo.create(dbName,
                outputTableName, null));
        HCatSchema s = HCatInputFormat.getTableSchema(job);
        System.err.println("INFO: output schema explicitly set for writing:"
                + s);
        HCatOutputFormat.setSchema(job, s);
        job.setOutputFormatClass(HCatOutputFormat.class);
        return (job.waitForCompletion(true) ? 0 : 1);
    }

    public static void main(String[] args) throws Exception {
        int exitCode = ToolRunner.run(new WriteRC(), args);
        System.exit(exitCode);
    }
}