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public interface Tool
A tool interface that supports handling of generic command-line options.
Tool, is the standard for any Map-Reduce tool/application.
The tool/application should delegate the handling of
standard command-line options to ToolRunner.run(Tool, String[])
and only handle its custom arguments.
Here is how a typical Tool is implemented:
public class MyApp extends Configured implements Tool {
public int run(String[] args) throws Exception {
// Configuration processed by ToolRunner
Configuration conf = getConf();
// Create a JobConf using the processed conf
JobConf job = new JobConf(conf, MyApp.class);
// Process custom command-line options
Path in = new Path(args[1]);
Path out = new Path(args[2]);
// Specify various job-specific parameters
job.setJobName("my-app");
job.setInputPath(in);
job.setOutputPath(out);
job.setMapperClass(MyApp.MyMapper.class);
job.setReducerClass(MyApp.MyReducer.class);
// Submit the job, then poll for progress until the job is complete
JobClient.runJob(job);
}
public static void main(String[] args) throws Exception {
// Let ToolRunner handle generic command-line options
int res = ToolRunner.run(new Configuration(), new Sort(), args);
System.exit(res);
}
}
GenericOptionsParser,
ToolRunner| Method Summary | |
|---|---|
int |
run(String[] args)
Execute the command with the given arguments. |
| Methods inherited from interface org.apache.hadoop.conf.Configurable |
|---|
getConf, setConf |
| Method Detail |
|---|
int run(String[] args)
throws Exception
args - command specific arguments.
Exception
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