OASIS Mailing List ArchivesView the OASIS mailing list archive below
or browse/search using MarkMail.

 


Help: OASIS Mailing Lists Help | MarkMail Help

wsbpel message

[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]


Subject: RE: [wsbpel] Issue 36 - Proposal to vote - Multiple instances of event handler


On Point#1 I have the same interpretation.  On Point#2 I don’t see the problem.  We are not specifying any buffer mechanism for these message delivery semantics.  All we can say is that each message is assigned to a new instance of the handler and each instance of the handler has its own private variable for holding the message.  Implementations can worry about making sure there is no race at the message buffers if they have any.

 

 


From: Prasad Yendluri [mailto:pyendluri@webmethods.com]
Sent: Thursday, October 16, 2003 7:01 PM
To: Assaf Arkin
Cc: wsbpel@lists.oasis-open.org
Subject: Re: [wsbpel] Issue 36 - Proposal to vote - Multiple instances of event handler

 

I guess only when one tries put things in black and white himself, one sees these...

I need to seek some clarifications on the resolution..

1. The resolution does not talk about partnerLink, portType and operation attributes that
    currently exist on <onMessage/> event handler. I take that is because <onEvent> added
    the messageType attribute but did not take away the other attributes. This is perhaps obvious
    but I better seek a clarification prior to modifying the spec.

2.  Item 6 in the resolution says,

6. Upon receipt of the input message the event handler assigns the input
message to the variable before proceeding to perform the event handler
activity.

    Isn't there a timing issue here still? This is almost similar to the original issue, in that
    what if another message comes through prior to the eventHandler actually having a
    chance to copy out the value to the local variable?

Thanks for the clarifications.

Prasad

-------- Original Message --------

Subject:

[wsbpel] Issue 36 - Proposal to vote - Multiple instances of event handler

Date:

Fri, 10 Oct 2003 18:47:16 -0700

From:

Assaf Arkin <arkin@intalio.com>

To:

wsbpel@lists.oasis-open.org

 

Proposal to resolve issue 36.
 
The semantics of event handler would be changed to allow the variable
used to capture the input message to be treated local to the event
handler instance:
 
1. Rename eventHandler/onMessage to eventHandler/onEvent
 
2. The name of the variable is given in the variable attribute.
 
3. The attribute messageType specifies the variable type by referencing
the message type definition using its QName.
 
4. The variable type must be the same as the type of the input message
defined by referenced operation.
 
5. The event handler declares a variable of that name and type that is
scoped to the event handler activity.
 
6. Upon receipt of the input message the event handler assigns the input
message to the variable before proceeding to perform the event handler
activity.
 
7. Since the variable is scoped to that activity, two instances of the
activity (whether executed seriallly or
concurrently) do not operate on the same variable.
 
arkin
 


[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]