public static void addDatasource(String sourcePath,String destPath,DsDef newDatasource) throws IOException {
  addDatasources(sourcePath,destPath,Collections.singleton(newDatasource));
}

public static void addDatasource ( String sourcePath , String destPath , DsDef newDatasource ) throws IOException { addDatasources ( sourcePath , destPath , Collections . singleton ( newDatasource ) ) ; }
creates a new rrd file with one more datasource in it . rrd file is created based on the existing one ( the original rrd file is not modified at all ) . all data from the original rrd file is copied to the new one .
