package hip.ch6.joins;
import hip.util.Cli;
import hip.util.CliCommonOpts;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;
import java.io.IOException;
public class FilterProjection extends Configured implements Tool {
/**
* Main entry point for the example.
*
* @param args arguments
* @throws Exception when something goes wrong
*/
public static void main(final String[] args) throws Exception {
int res = ToolRunner.run(new Configuration(), new FilterProjection(), args);
System.exit(res);
}
/**
* The MapReduce driver - setup and launch the job.
*
* @param args the command-line arguments
* @return the process exit code
* @throws Exception if something goes wrong
*/
public int run(final String[] args) throws Exception {
Cli cli = Cli.builder().setArgs(args).addOptions(CliCommonOpts.MrIoOpts.values()).build();
int result = cli.runCmd();
if (result != 0) {
return result;
}
Path inputPath = new Path(cli.getArgValueAsString(CliCommonOpts.MrIoOpts.INPUT));
Path outputPath = new Path(cli.getArgValueAsString(CliCommonOpts.MrIoOpts.OUTPUT));
Configuration conf = super.getConf();
Job job = new Job(conf);
job.setJarByClass(FilterProjection.class);
job.setMapperClass(JoinMap.class);
job.setNumReduceTasks(0);
FileInputFormat.setInputPaths(job, inputPath);
FileOutputFormat.setOutputPath(job, outputPath);
return job.waitForCompletion(true) ? 0 : 1;
}
public static class JoinMap extends Mapper<LongWritable, Text, Text, Text> {
@Override
protected void map(LongWritable offset, Text value, Context context)
throws IOException, InterruptedException {
User user = User.fromText(value);
if (user.getAge() >= 30) {
context.write(new Text(user.getName()),
new Text(user.getState()));
}
}
}
}