Why use a JSF ExceptionHandlerFactory instead of redirection?

by

The particular example does only one useful thing: it saves the view ID as a request attribute so that you can use for example

<h:link value="Go back to previous page" outcome="#{currentViewId}" />

But this is not tremendously useful as the raw request URI is already available by the <error-page>‘s default request attribute javax.servlet.error.request_uri.

<h:outputLink value="#{requestScope['javax.servlet.error.request_uri']}">Go back to previous page</h:outputLink>

However one thing what a custom ExceptionHandler is really useful for is that it allows you to deal with exceptions during ajax requests. By default they have namely no single form of helpful feedback in the client side. Only in Mojarra with project stage set to “Development” you’ll see a bare JavaScript alert message with the exception message. But that’s it. There is no single form of feedback in “Production” stage. With a custom ExceptionHandler you would be able to parse the web.xml to find the error page locations, create a new UIViewRoot with it and force JSF to set ajax rendering to @all.

So, basically:

String errorPageLocation = "/WEB-INF/errorpages/500.xhtml";
context.setViewRoot(context.getApplication().getViewHandler().createView(context, errorPageLocation));
context.getPartialViewContext().setRenderAll(true);
context.renderResponse();

See also this related question: What is the correct way to deal with JSF 2.0 exceptions for AJAXified components? and this blog: Full Ajax Exception Handler.

More Related Contents:

  1. Sometimes I see JSF URL is *.jsf, sometimes *.xhtml and sometimes /faces/*. Why?
  2. Overview of all JSF-related web.xml context parameter names and values [closed]
  3. javax.faces.application.ViewExpiredException: View could not be restored
  4. How and when should I load the model from database for h:dataTable
  5. Get JSF managed bean by name in any Servlet related class
  6. How to save uploaded file in JSF
  7. Invoke JSF managed bean action on page load
  8. JSF implementations and component libraries [closed]
  9. Default action to execute when pressing enter in a form
  10. What is the usefulness of statelessness in JSF?
  11. How to compare a char property in EL
  12. PrimeFaces CSS skin not showing in login page, also JavaScript undefined errors
  13. How does EL empty operator work in JSF?
  14. Creating master-detail table and dialog, how to reuse same dialog for create and edit
  15. What is the function of @this exactly?
  16. How to insert special characters like & and < into JSF components' value attribute?
  17. How to conditionally render an f:selectItem tag?
  18. Running JSF 2.0 on Servlet 2.4 container
  19. Customize primefaces chart
  20. How to display my application’s errors in JSF?
  21. How to get both label and value from f:selectItems
  22. How to use EL in PrimeFaces oncomplete attribute which is updated during action method
  23. Exception: could not find Factory: javax.faces.context.FacesContextFactory
  24. How create a custom converter in JSF 2?
  25. Set a default time zone for f:convertDateTime
  26. JSF 2.0: How to override base renderers with custom ones?
  27. @PreDestroy never called on @ViewScoped [duplicate]
  28. Populate p:selectOneMenu based on another p:selectOneMenu in each row of a p:dataTable
  29. Initialize a composite component based on the provided attributes
  30. Server side HTML sanitizer/cleanup for JSF

Leave a Comment