[jbossseam-issues] [JBoss JIRA] Commented: (JBSEAM-2209) Improve ways to transfer state information from a nested conversation to the parent conversation context

Wolfgang Schwendt (JIRA) jira-events at lists.jboss.org
Sat Aug 30 14:47:38 EDT 2008

    [ https://jira.jboss.org/jira/browse/JBSEAM-2209?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12427459#action_12427459 ] 

Wolfgang Schwendt commented on JBSEAM-2209:

Thanks for the info, Pete.  I understand that ManagedEntityIdentityInterceptor causes a huge performance penalty and therefore is likely to be replaced by a  more efficient approach. As for the state transfer between a nested conversation and its parent conversation, my approach for the time being is the workaround shortly mentioned above already (state transfer to a DTO object stored in the parent conversation context, which has not the ManagedEntityIdentityInterceptor attached).

> Improve ways to transfer state information from a nested conversation to the parent conversation context
> --------------------------------------------------------------------------------------------------------
>                 Key: JBSEAM-2209
>                 URL: https://jira.jboss.org/jira/browse/JBSEAM-2209
>             Project: Seam
>          Issue Type: Bug
>          Components: Core
>            Reporter: Wolfgang Schwendt
>            Priority: Critical
>         Attachments: nestedConversationsBehavior-Screenshots.pdf, nestedConversationsBehavior.zip
> When a nested conversation ends, it is difficult to transfer an ending result back to the parent conversation.    The following approach is currently not viable with Seam: We cannot simply access a component from the parent conversation and call a property Setter of this component with the ending result of the nested conversation supplied as argument for this Setter. The reason is that when a component from the parent conversation is called while the nested conversation is still in progress, the ManagedEntityIdentityInterceptor saves wrappers for the called component in the scope of the nested conversation (!) and not the scope of the parent conversation. So once the nested conversation scope gets destroyed at the end of the nested conversation, the saved wrappers for the component from the parent conversation get destroyed as well.
> Scenario:
> Suppose that we have a component AA in the conversation context with a field reference named 'bb' to an another component Q. At some point of time this reference is moved by the ManagedEntityIdentityInterceptor to a conversation-scoped context variable with the name "AA.bb".  Then we start a nested conversation. While the nested conversation is in progress, we can call a method of component AA and successfully access the field bb because at the time of the method invocation, the ManagedEntityIdentityInterceptor can retrieve the saved wrapper for field bb from the parent conversation context and put the contained reference into the component AA.  
> But then we call a method of component AA which changes the field bb.   At the end of this method invocation,  the ManagedEntityIdentityInterceptor moves the new value of reference field bb to a wrapper saved in the nested (!) conversation context.   Afterwards we end the nested conversation and the parent conversation resumes again.      When we then call a method of component AA again, the ManagedEntityIdentityInterceptor retrieves the wrapper for  field bb from the conversation context.  But this wrapper contains the old value for field bb, not the new value.    Note that the wrapper with the new value for field bb got destroyed already at the time when the nested conversation context was destroyed.
> http://www.jboss.com/index.html?module=bb&op=viewtopic&t=118936&start=30
> Feature request regarding nested conversations
> Tue Sep 18, 2007 00:28 AM
> http://www.jboss.com/index.html?module=bb&op=viewtopic&t=121852
> Nested Conversations (tricky interceptor)
> Mon Oct 22, 2007 11:03 AM 

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