tapestry-users mailing list archives

The basic problem: one page's listener calls another page's listener  
(after activating the other page). The other page records a  
validation error, and that causes a NullPointerException deep in  
Tapestry's guts.

The details:

I have two pages (Subscribe and SubscribeAlternateLink), both of  
which involve the user entering/selecting a URL. Once the URL is  
entered, they share the same logic -- and I want either one of them  
to end up on the Subscribe page in case of an error.

So I have this page delegate its subscribe() listener to the other page:

     public abstract class SubscribeAlternateLink extends MyBasePage {
     ...
         public IPage subscribe(String url) {
             Subscribe subscribePage = getPage(Subscribe.class);
             subscribePage.setUrl(url);
             getRequestCycle().activate(subscribePage);
             return subscribePage.subscribe();
         }
     ...
     }

And the other page has a URL field, which will show the URL the user  
entered, with an error:

     public abstract class Subscribe
             extends MyBasePage {

         @Bean( value=ReaderValidation.class )
         public abstract IValidationDelegate getFormValidation();

         @Component(type="TextField", bindings = {
             "value=ognl:url",
             "validators=validators:required" } )
         public abstract TextField getUrlField();
         public abstract String getUrl();
         public abstract void setUrl(String url);

         public IPage subscribe() {

             if(getFormValidation().getHasErrors())
                 return this;

             try {
                 // ... do subscription ...
             } catch(SubscriptionException e) {
                 getFormValidation().record(getUrlField(),  
e.getMessage()); // ***
                 return this;
             }
             // ... follow-up stuff ...
         }
     }

When submitting from the Subscribe page, errors get recorded fine.

When submitting from the SubscribeAlternateLink, I get an exception  
on the line marked ***:

     java.lang.NullPointerException: Parameter fieldName must not be  
null.
	• org.apache.hivemind.util.Defense.notNull(Defense.java:41)
	• org.apache.tapestry.valid.FieldTracking.<init>(FieldTracking.java:59)
	• org.apache.tapestry.valid.ValidationDelegate.findCurrentTracking 
(ValidationDelegate.java:279)
	• org.apache.tapestry.valid.ValidationDelegate.record 
(ValidationDelegate.java:225)
	• org.apache.tapestry.valid.ValidationDelegate.record 
(ValidationDelegate.java:207)
	• org.apache.tapestry.valid.ValidationDelegate.record 
(ValidationDelegate.java:240)
	• com.dci.cyclonereader.web.Subscribe.subscribe(Subscribe.java:41)
	• com.dci.cyclonereader.web.SubscribeAlternateLink.subscribe 
(SubscribeAlternateLink.java:28)

It looks like the URL component on the Subscribe page isn't fully  
initialized. Is this a bug? Or do I need to do something more to  
initialize the Subscribe page?

Cheers,

Paul


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