protected Command doCreateCommand(ModifierHelper aHelper) { if (!aHelper.isComplete()) { setStatus(ERROR); return null; } Command command = null; if (aHelper.getFeature().isMany()) command = createManyCommand(aHelper); else command = createSingleCommand(aHelper); if (null != command) { List localHelpers = ModifierHelperRegistry.getInstance().getHelpers(aHelper); if (null != localHelpers) { extendedHelpers.addAll(localHelpers); } } return command; }