Example usage for org.apache.hadoop.mapreduce TaskAttemptContext getMapperClass

Introduction

In this page you can find the example usage for org.apache.hadoop.mapreduce TaskAttemptContext getMapperClass.

Prototype

public Class<? extends Mapper<?, ?, ?, ?>> getMapperClass() throws ClassNotFoundException;

Source Link

Document

Get the Mapper class for the job.

Usage

From source file:org.apache.tez.mapreduce.processor.map.MapProcessor.java

License:Apache License

private void runNewMapper(final JobConf job, MRTaskReporter reporter, final MRInputLegacy in,
        KeyValueWriter out) throws IOException, InterruptedException {

    // Initialize input in-line since it sets parameters which may be used by the processor.
    // Done only for MRInput.
    // TODO use new method in MRInput to get required info
    //in.initialize(job, master);

    // make a task context so we can get the classes
    org.apache.hadoop.mapreduce.TaskAttemptContext taskContext = getTaskAttemptContext();

    // make a mapper
    org.apache.hadoop.mapreduce.Mapper mapper;
    try {/* w w w  . java  2  s  . c  om*/
        mapper = (org.apache.hadoop.mapreduce.Mapper) ReflectionUtils.newInstance(taskContext.getMapperClass(),
                job);
    } catch (ClassNotFoundException cnfe) {
        throw new IOException(cnfe);
    }

    org.apache.hadoop.mapreduce.RecordReader input = new NewRecordReader(in);

    org.apache.hadoop.mapreduce.RecordWriter output = new NewOutputCollector(out);

    org.apache.hadoop.mapreduce.InputSplit split = in.getNewInputSplit();

    updateJobWithSplit(job, split);

    org.apache.hadoop.mapreduce.MapContext mapContext = new MapContextImpl(job, taskAttemptId, input, output,
            committer, processorContext, split, reporter);

    org.apache.hadoop.mapreduce.Mapper.Context mapperContext = new WrappedMapper().getMapContext(mapContext);

    input.initialize(split, mapperContext);
    mapper.run(mapperContext);
    // Set progress to 1.0f if there was no exception,
    reporter.setProgress(1.0f);

    this.statusUpdate();
    input.close();
    output.close(mapperContext);
}

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