code: public long count() throws Exception {
  		final String id = new AbstractID().toString();
  
  		output(new Utils.CountHelper<T>(id)).name("count()");
  
  		JobExecutionResult res = getExecutionEnvironment().execute();
  		return res.<Long> getAccumulatorResult(id);
  	}
docs: Convenience method to get the count (number of elements) of a DataSet.
  
  @return A long integer that represents the number of elements in the data set.