// has problems finding resources like files specified in
// parameters if the xml file was specified as an absolute path.
CompositeActor toplevel = (CompositeActor) parser.parse(null, new File(
xmlFileName).toURI().toURL());
_manager = new Manager(toplevel.workspace(), "MoMLSimpleApplication");
toplevel.setManager(_manager);
toplevel.addChangeListener(this);
_manager.addExecutionListener(this);
_manager.execute();