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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 byToolRunner
Configuration conf = getConf(); // Create a JobConf using the processedconf
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 { // LetToolRunner
handle generic command-line options int res = ToolRunner.run(new Configuration(), new Sort(), args); System.exit(res); } }
GenericOptionsParser
,
ToolRunner
Method Summary | |
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int |
run(String[] args)
Execute the command with the given arguments. |
Methods inherited from interface org.apache.hadoop.conf.Configurable |
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getConf, setConf |
Method Detail |
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int run(String[] args) throws Exception
args
- command specific arguments.
Exception
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