(I posted this to the "dev" email list by accident, so I am reposting here with
a bit more information...)
I am implementing a multi-step registration wizard which functions as follows:
1. Uses one backing bean per wizard page
2. Uses Tomahawk saveState to save model data between pages
3. "Next" button performs full-validation on all required and critical input
fields for each page
4. "Previous" button navigates back to the previous wizard page, without
performing any validation. However, if the user has entered any values on the
page, it pushes those values into the model/backing bean before navigating to
the previous page
I am using the "immediate" attribute on the "required" input components, along
with the "immediate" attribute on the "Previous" commandButton component, as
well as an actionListener which invokes a method to processUpdates() on the
UIViewRoot when the button is clicked. All this works fine, the user's entries
are saved to the model and restored when the come back to the page (even though
they have not been validated yet), and validation occurs when they hit the
"Next" button on every page.
Here's my problem though:
When the user navigates to a new page and does not enter ANY data for the
"required"/"immediate" input fields, then clicks the "Previous" button a Null
Pointer exception is thrown during the applyRequestValues() phase (see stack
trace below). However, if they actually enter data into each of the
"required"/"immediate" input fields everything works just fine. Also, if I
remove the "required" attribute, then the exception disappears but of course
there is no validation which runs when the user subsequently clicks the "Next"
button either so that is not really an option. Any ideas? I have set
breakpoints in many places, but cannot figure out exactly why this exception is
being thrown or how to get around it.
javax.servlet.ServletException
javax.faces.webapp.FacesServlet.service(FacesServlet.java:156)
org.apache.myfaces.webapp.filter.ExtensionsFilter.doFilter(ExtensionsFilter.java:144)
root cause
java.lang.NullPointerException
javax.faces.component.UIViewRoot._broadcastForPhase(UIViewRoot.java:112)
javax.faces.component.UIViewRoot.processDecodes(UIViewRoot.java:136)
org.apache.myfaces.lifecycle.LifecycleImpl.applyRequestValues(LifecycleImpl.java:219)
org.apache.myfaces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:71)
javax.faces.webapp.FacesServlet.service(FacesServlet.java:137)
org.apache.myfaces.webapp.filter.ExtensionsFilter.doFilter(ExtensionsFilter.java:144)
