code: private static DataSet<Long> getVertexDataSet(ExecutionEnvironment env, ParameterTool params) {
  		if (params.has("vertices")) {
  			return env.readCsvFile(params.get("vertices")).types(Long.class).map(
  				new MapFunction<Tuple1<Long>, Long>() {
  					public Long map(Tuple1<Long> value) {
  						return value.f0;
  					}
  				});
  		} else {
  			System.out.println("Executing Connected Components example with default vertices data set.");
  			System.out.println("Use --vertices to specify file input.");
  			return ConnectedComponentsData.getDefaultVertexDataSet(env);
  		}
  	}
docs: *************************************************************************