request.setAttribute("selectedExecutionDegree", selectedExecutionDegree); form.set("degree", selectedExecutionDegree.getIdInternal());
final ExecutionDegree selectedExecutionDegree = getSelectedExecutionDegree(form, registration, executionPeriod, executionDegrees); if (selectedExecutionDegree == null) { addActionMessage(request, "errors.impossible.operation"); return mapping.getInputForward(); }
	private ActionForward prepareSelectCoursesInformation(ActionMapping mapping, ActionForm actionForm,			HttpServletRequest request, final Registration registration, final ExecutionPeriod executionPeriod) {		final DynaActionForm form = (DynaActionForm) actionForm;				final List<ExecutionDegree> executionDegrees = executionPeriod.getExecutionYear()				.getExecutionDegreesFor(DegreeType.DEGREE);		if (executionDegrees.isEmpty()) {			addActionMessage(request, "errors.impossible.operation");			return mapping.getInputForward();		}		final ExecutionDegree selectedExecutionDegree = getSelectedExecutionDegree(form, registration,				executionPeriod, executionDegrees);		if (selectedExecutionDegree == null) {			addActionMessage(request, "errors.impossible.operation");			return mapping.getInputForward();		}		request.setAttribute("selectedExecutionDegree", selectedExecutionDegree);		form.set("degree", selectedExecutionDegree.getIdInternal());		sortExecutionDegreesByDegreeName(executionDegrees);		request.setAttribute("executionDegrees", ExecutionDegreesFormat				.buildLabelValueBeansForExecutionDegree(executionDegrees, getResources(request,				"ENUMERATION_RESOURCES"), request));		request.setAttribute("attendingExecutionCourses", registration				.getAttendingExecutionCoursesFor(executionPeriod));		request.setAttribute("executionCoursesFromExecutionDegree", selectedExecutionDegree				.getDegreeCurricularPlan().getExecutionCoursesByExecutionPeriod(executionPeriod));		return mapping.findForward("selectCourses");	}