[jira] [Resolved] (TAP5-1284) When using @PageActivationContext and override a no-args activate event handler of parent page, the handler called too soon

["Howard M. Lewis Ship (Resolved) (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/TAP5-1284?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Howard M. Lewis Ship resolved TAP5-1284.
----------------------------------------

    Resolution: Invalid
      Assignee: Howard M. Lewis Ship

Sometimes Tapestry "is what it is". Perhaps the activate event should be followed by an additional event, used to verify the page. That would eliminate some of the problems related to order of operations between base-classes and sub-classes.

Or you could simply avoid using base classes. Old habits die hard.
                
> When using @PageActivationContext and override a no-args activate event handler of parent page, the handler called too soon
> ---------------------------------------------------------------------------------------------------------------------------
>
>                 Key: TAP5-1284
>                 URL: https://issues.apache.org/jira/browse/TAP5-1284
>             Project: Tapestry 5
>          Issue Type: Bug
>          Components: tapestry-core
>    Affects Versions: 5.2.0
>            Reporter: Alexander Gavrilov
>            Assignee: Howard M. Lewis Ship
>            Priority: Critical
>
> It appears that the overrided onActivate() method is called before the @PageActivationContext logic, which means the following can fail:
> public class BasePage { 
>     private MyEntity entity; 
>       
>     protected void setEntity(MyEntity entity) { 
>          this.entity = entity; 
>     } 
>        
>     protected void onActivate() { 
>         if (entity == null) throw new RuntimeException("Entity not found."); 
>     } 
> } 
> public class ConcreteClass { 
>     @PageActivationContext 
>     private MyEntity entity; 
>     protected void onActivate() { 
>         setEntity(entity); 
>         super.onActivate(); 
>     } 
> } 
> Workaround is do not use methods overriding. 
> The problem is the consecuence of Howard's approach:  "if the child class *overrides* a method of the parent, then the overridden method will be invoked only by the parent class". When Tapestry performs transformation it skips OnEventWorker advice, which invoke event handler method of subclass and add it only for parent class. And required for @PageActivationContext chain of invocation breaks. My approach is that if some class override some event handler method of some class then Tapestry should stop advaicing parent class method invocation and should rely on subclass method definition and is the subclass implementor responibility to invoke parent class method.   

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