code: private void initComparators() {
  		TupleMRConfigBuilder.initializeComparators(context.getHadoopContext()
  		    .getConfiguration(), tupleMRConfig);
  		customComparators = new RawComparator<?>[maxDepth + 1];
  		for(int i = minDepth; i <= maxDepth; i++) {
  			SortElement element = tupleMRConfig.getCommonCriteria().getElements().get(i);
  			if(element.getCustomComparator() != null) {
  				customComparators[i] = element.getCustomComparator();
  			}
  		}
  	}
docs: Initialize the custom comparators. Creates a quick access array for the
  custom comparators.