code: private static DataSet<Long> getPagesDataSet(ExecutionEnvironment env, ParameterTool params) {
  		if (params.has("pages")) {
  			return env.readCsvFile(params.get("pages"))
  				.fieldDelimiter(" ")
  				.lineDelimiter("\n")
  				.types(Long.class)
  				.map(new MapFunction<Tuple1<Long>, Long>() {
  					@Override
  					public Long map(Tuple1<Long> v) {
  						return v.f0;
  					}
  				});
  		} else {
  			System.out.println("Executing PageRank example with default pages data set.");
  			System.out.println("Use --pages to specify file input.");
  			return PageRankData.getDefaultPagesDataSet(env);
  		}
  	}
docs: *************************************************************************