RE: [wsrp] handleEvent or handleEvents?

From
Rich Thompson <>
Date
2004-12-14T16:10:51+00:00
ID
Thread
RE: [wsrp] handleEvent or handleEvents?
Richard, 

Would the following update to #2 address
your concern?

2. Events are independent notifications that something
has occurred, which receiving portlets may use to impact their state.

Rich

Richard Jacob <>

12/13/2004 01:37 PM

To

Andre Kramer <>

cc



Subject

RE: [wsrp] handleEvent or
handleEvents?

One other important point to me is that we really should understand the

nature of events.

Portlets shouldn't rely on event delivery and thus also shouldn't rely
on

correct event processing.

We also do not deliver failure events back to the portlet issuing the

original event (this was the first design we had).

Therefore we might want to ask ourselves what event failures are really
for

and who will be doing what with this information.

Key point for me is that we shouldn't try to implement a (relyable)

messaging system based on events, i.e. we shouldn't add any

atomicy,rollback, etc. rules to eventing.

Mit freundlichen Gruessen / best regards,

        Richard Jacob

______________________________________________________

IBM Lab Boeblingen, Germany

Dept.8288, WebSphere Portal Server Development

WSRP Standardization Technical Lead

Phone: ++49 7031 16-3469  -  Fax: ++49 7031 16-4888

Email: mailto:

                    
                     
                     
          

             Andre Kramer      
                     
                     

             <andre.kramer@eu.  
                     
                    

             citrix.com>    
                     
                     To

                    
                  
          

             12/13/2004 03:17    
                     
                cc 

             PM        
                     
                     
       

                    
                     
                     
  Subject 

                    
                  RE: [wsrp]
handleEvent or           

                    
                  handleEvents?
                     

                    
                     
                     
          

                    
                     
                     
          

                    
                     
                     
          

                    
                     
                     
          

                    
                     
                     
          

                    
                     
                     
          

Recognizing that event processing occurs in rounds would also help the

presentation. Each round involves a consumer delivering a batch of events

to the producer and optionally receiving back a further batch of events

(and failure events) to process.

Regards,

Andre

From: Rich Thompson [mailto:]

Sent: 13 December 2004 14:10

To: 

Subject: Re: [wsrp] handleEvent or handleEvents?

The F2F decision was to drop to handleEvent for now due to the issues

involved in handling faults in the batched case. We should work on these

and seek to restore the nature to a batch operation for the reasons you

list. Basically the solution should respect the current overall design:

1. Portlets are loosely coupled components integrated onto the page by
the

Consumer.

2. Events are notifications that something has occurred which other

components may use to impact their own state.

3. There are times when a Consumer will care what failures have occurred

(e.g. for retry purposes)

I think if we agree to these guidelines, then relatively simple solutions

to the failure issues in the batch operation can be designed. Any comments

on these as guidelines before we try and design/debate a solution?

Rich

                    
                     
                     
          

 Andre Kramer                  
                     
                     

 <>          
                     
             

                    
                     
                     
          

                    
                     
                     
       To 

 12/10/2004 07:06 AM                
                -open

                    
                     
          .org          
       

                    
                     
                     
       cc 

                    
                     
                     
          

                    
                     
                     
  Subject 

                    
                     
          [wsrp] handleEvent or 

                    
                     
          handleEvents?        

                    
                     
                     
          

                    
                     
                     
          

                    
                     
                     
          

                    
                     
                     
          

                    
                     
                     
          

                    
                     
                     
          

                    
                     
                     
          

                    
                     
                     
          

                    
                     
                     
          

                    
                     
                     
          

My comment is on the current 2.0 draft, so I am sending it to the TC list,

even though it is specific to coordination. As initially written,

handleEvent is constrained to only deliver a single (IN) event and requires

the consumer to not deliver a second event while the first is being

processed (but multiple events can be returned by a portlet). This seems
an

unworkable solution to me because of (1) network latency and (2) event

processing logically occurs in rounds. Should we start with handleEvents

rather than try to discuss a handleEvent?

Regards,

Andre

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