public void handle()

in tobago-core/src/main/java/org/apache/myfaces/tobago/context/TobagoExceptionHandler.java [58:169]
101 lines of code
19 McCabe index (conditional complexity)

  public void handle() throws FacesException {

    final FacesContext facesContext = FacesContext.getCurrentInstance();

    if (facesContext.getPartialViewContext().isAjaxRequest()) {
      final Iterator<ExceptionQueuedEvent> events = getUnhandledExceptionQueuedEvents().iterator();
      if (events.hasNext()) {
        final Throwable exception = events.next().getContext().getException();
        if (!(exception instanceof AbortProcessingException)) {
          final String errorPageLocation = WebXmlUtils.getErrorPageLocation(exception);

          if (errorPageLocation != null
              && (facesContext.getCurrentPhaseId() != PhaseId.RENDER_RESPONSE
              || !facesContext.getExternalContext().isResponseCommitted())) {

            try {
              final HttpServletRequest request = (HttpServletRequest) facesContext.getExternalContext().getRequest();
              final HttpServletResponse response =
                  (HttpServletResponse) facesContext.getExternalContext().getResponse();

              request.setAttribute("jakarta.servlet.error.exception", exception);
              request.setAttribute("jakarta.servlet.error.exception_type", exception.getClass());
              request.setAttribute("jakarta.servlet.error.message", exception.getMessage());
              request.setAttribute("jakarta.servlet.error.request_uri", request.getRequestURI());
              request.setAttribute("jakarta.servlet.error.status_code", HttpServletResponse.SC_INTERNAL_SERVER_ERROR);

              response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);

              renderErrorPage(facesContext, errorPageLocation);
              cleanupExceptionQueuedEvents();
            } catch (final IOException e) {
              throw new FacesException(e);
            }
          } else {
            LOG.debug("Can't return an error page. errorPageLocation='{}'", errorPageLocation);
          }
        }
      }
    } else {
      final Iterator<ExceptionQueuedEvent> iterator = getUnhandledExceptionQueuedEvents().iterator();
      while (iterator.hasNext()) {
        final ExceptionQueuedEvent event = iterator.next();
        final ExceptionQueuedEventContext context = (ExceptionQueuedEventContext) event.getSource();
        Throwable cause = this.getWrapped().getRootCause(context.getException());
        if (cause == null) {
          cause = context.getException();
        }
        final NavigationHandler nav = facesContext.getApplication().getNavigationHandler();

        if (cause instanceof ViewExpiredException
            || cause != null && cause.getCause() instanceof ViewExpiredException) {
          final ViewExpiredException viewExpiredException = (ViewExpiredException)
              (cause instanceof ViewExpiredException ? cause : cause.getCause());
          try {
            facesContext.addMessage(null,
                new FacesMessage(FacesMessage.SEVERITY_WARN,
                    "The view has been expired!",
                    "Please check the given data or try to start from the beginning."));
            nav.handleNavigation(facesContext, null, viewExpiredException.getViewId());
            facesContext.renderResponse();
            LOG.debug("Handling ViewExpiredException on viewId: {}", viewExpiredException.getViewId());
          } finally {
            iterator.remove();
          }
        } else {
          try {
            final boolean error404 = cause instanceof FileNotFoundException
                || cause != null && cause.getCause() instanceof FileNotFoundException;
            final FacesMessage message;
            if (error404) {
              message = new FacesMessage(FacesMessage.SEVERITY_ERROR,
                  "The page was not found!",
                  "The requested page was not found!");
              facesContext.getExternalContext().setResponseStatus(HttpServletResponse.SC_NOT_FOUND);
              LOG.warn("Handling 404 exception.");
            } else {
              message = new FacesMessage(FacesMessage.SEVERITY_ERROR,
                  "An unknown error has occurred!" + " xxx",
                  "An unknown error has occurred!" + " xxx");
              facesContext.getExternalContext().setResponseStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
              LOG.warn("Handling 500 exception.", cause);
            }
            facesContext.addMessage(null, message);
            final String viewId = "/tobago/error.xhtml";

            // when the rendering was not yet started, we can forward to an error page
            if (event.getContext().getPhaseId().getOrdinal() < PhaseId.RENDER_RESPONSE.getOrdinal()) {
              nav.handleNavigation(facesContext, null, viewId);
              facesContext.renderResponse();
            } else {
              final HttpServletResponse response =
                  (HttpServletResponse) facesContext.getExternalContext().getResponse();
              response.resetBuffer(); // undo rendering, if you can.
              final ViewHandler viewHandler = facesContext.getApplication().getViewHandler();
              final ViewDeclarationLanguage vdl = viewHandler.getViewDeclarationLanguage(facesContext, viewId);
              final UIViewRoot viewRoot = viewHandler.createView(facesContext, viewId);
              vdl.buildView(facesContext, viewRoot);
              facesContext.getApplication().publishEvent(facesContext, PreRenderViewEvent.class, viewRoot);
              vdl.renderView(facesContext, viewRoot);
            }
          } catch (Exception e) {
            LOG.error("Exception while exception handling!", e);
          } finally {
            facesContext.responseComplete();
            iterator.remove();
          }
        }
      }
    }

    super.handle();
  }