SOA concepts and Workflow OO Classes: Hybird Service Enablers?

[Mike Gambier]

Some more thoughts on this...and I think in the end I've answered my own questions :)

 

After some interesting discussion we've decided to keep our Workflow-enabled OO Classes separate from our SOA Business Application Objects (effectively above them) for 3 main reasons:

 

1. We will want the capacity to use 'instance-independent' modelling in Workflow whereas Services will want to deal with proper valid instances with legitimate keys and therefore null instances are not allowed.

 

2. We may want to interpret and handle exceptions (Temporary, System and Application) in a Workflow framework in a different way than Services do, particularly the handling of Temporary Exceptions and the use of CX_BO_TEMPORARY with SWWERRE.

 

3. We will need to allow Workflow functional changes to be made without risking the availability of the the business logic to the service layer. This should build in a certain amount of resilience and keep the code streams apart a bit more wherever possible.

 

By keeping these two layers separate it also allows us to consider heavier instantiation of Workflow-enabled objects with the possibility of building in the implicit relationships with Parents/Children/Siblings whilst at the same time keeping the Service-based operations as light as possible. 

 

Services by their nature are supposed to be more short-lived in terms of their LUW (akin to a new variety of BAPI call) so a light instance is better and the performance gains of buffering much less important. Whereas for Workflow the LUW could be extended considerably and the benefits of keeping static data held in memory could pay dividends across the system as a whole.

 

At least that's the current plan...

 

Mike GT

 


From: madgambler at hotmail.com
To: sap-wug at mit.edu
Subject: SOA concepts and Workflow OO Classes: Hybird Service Enablers?
Date: Tue, 24 Mar 2009 09:13:37 +0000



Fellow WUGgers,
 
We're considering launching ourselves into the SOA age over here and are starting to build the various layers inside SAP to cope with such delightfully exotic things as proxies, service classes, GDT mappers and application objects to suppor processing XML/SOAP interfaces. Woo :)
 
All neato stuff but it occurs to me that the innermost layer of our SOA framework could be quite powerful if it was also 'Workflow-enabed'. By that I mean our SOA Application Objects could support both services and Workflows if they became proper encapsulations of Business Logic that are open to all calls, both internal and external.
 
At the same time I'm also trying to convince people that some of the richness of the 'old' BOR framework should be kept in our new SOA Application Objects. For example, the ability for objects to 'know' about each other within a logical relationship (Parent/Child/Sibling). Has anyone any tips in this area? 
 
My current leanings are to abstract the relationships so that common 'GetRelationships' or 'GetParents' or 'GetSiblings' or 'GetChildren' methods could be modelled and possibly implemented on all of our Application Objects and become the OO equivalents of instance virtual attributes that could always be accessible if not actually implemented for every object.
 
We obviously want to avoid very heavy instantion and buffering of our Application Objects so I expect a lot of the attributes they possess are likely to be hidden behind accessor Public Methods and hit the databse on demand only. But even the concept of a unified 'Key' is quite a challenge in OO to support if we want to move away from an 'old' SWO_TYPEID string. Has anyone thought up a way of even doing that without having to resort to a TYPE ANY?

Being a novice to the 'new' OO representation of Business Objects my only other intention at the moment is to consider adding IF_WORKFLOW as a common interface on the Superclass for our Business Objects to inherit as standard. But perhaps there are other things I need to consider too?
 
Do we have any 'standard' OO Business Objects to examine and plunder?
 
Regards,
 
Mike GT
 
 



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