LoadSplit split = getLoadSplit();
MapContext<NullWritable, GridmixRecord, GridmixKey, GridmixRecord> mapcontext = new MapContextImpl<NullWritable, GridmixRecord, GridmixKey, GridmixRecord>(
conf, taskid, reader, writer, committer, reporter, split);
// context
Context ctxt = new WrappedMapper<NullWritable, GridmixRecord, GridmixKey, GridmixRecord>()
.getMapContext(mapcontext);
reader.initialize(split, ctxt);
ctxt.getConfiguration().setBoolean(MRJobConfig.MAP_OUTPUT_COMPRESS, true);
CompressionEmulationUtil.setCompressionEmulationEnabled(
ctxt.getConfiguration(), true);
LoadJob.LoadMapper mapper = new LoadJob.LoadMapper();
// setup, map, clean
mapper.run(ctxt);