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Web Services UML or BPEL4WS  RSS feed

 
HS Thomas
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Hi,
Can UML be used instead of BPEL4WS at the business level, that is.
I imagine UML will be continued to be used at the technical design level as I can't see that the cornerstones of OO(interfaces,classes etc) will be done away with at the design level unless there will be some hidden automatic mapping between the two levels.
regards
[ May 20, 2003: Message edited by: HS Thomas ]
 
Lasse Koskela
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Originally posted by HS Thomas:
Can UML be used instead of BPEL4WS at the business level, that is.

Hi again
UML and BPEL are two very different beasts. UML can be used to visualize software design. BPEL can be used to describe (not visualize) automated business processes. "UML is boxes and arrows" while "BPEL is XML"...
 
HS Thomas
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Hi Lasse ,
"UML is boxes and arrows" while "BPEL is XML"...

Yes, I had forgotten that Web Services was almost purely XML. A Web Service XML (BPEL)encapsulates and describes the data and process and can be converted to Java objects or classes and vice versa.
Ok, now I see where WS could be heading.
As I can't see how a developer can work with XML and practise OO , refactoring etc. they'd have to convert to Java classes first, do the business and convert them back to XML. Is that right?
The XML I know doesn't exactly enforce re-usability unless it's generated from Java classes ..
regards
[ May 20, 2003: Message edited by: HS Thomas ]
 
Lasse Koskela
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Originally posted by HS Thomas:
As I can't see how a developer can work with XML using OO , refactoring etc. they'd have to convert to Java classes first, do the business and convert them back to XML. Is that right?

Yes, the service needs to convert the incoming XML message into an object of some kind representing the application-specific request, for example, an instance of a Java class called com.company.business.PurchaseOrder. And the same goes for the client-end as well.
The XML is used in between mainly to allow interoperability via a common standard, the XML specification containing rules for encoding the application data being transmitted. The WS specifications (mainly SOAP) define some rules that the messages have to follow in order for the infrastructure to work (i.e. so that the server knows how to figure out which service an incoming SOAP request belongs to).
In general, XML should be used only on architectural edges (messaging with external partners, configuration files).

Originally posted by HS Thomas:
The XML I know doesn't exactly enforce re-usability unless it's generated from Java classes.

Well, XML enables reuse of services provided on a different platform than the client, for example.
 
HS Thomas
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In general, XML should be used only on architectural edges (messaging with external partners, configuration files).

I am not sure this is always going to be true, if you consider WS- Choreography and WS- Orchestration.
In the context of a single organisation, currently the architectural edges will bound the internal operational batch systems which provide files etc for external partners / other systems within the organisation to be processed in a leisurely fashion.
In the future, using WS- C and /or WS- O the architectural edges may be extended to include the external partners.
But what has really changed here ?
Currently the system/architecture produces files.
In the not too distant future, a system could produce WS- messages instead, which the external partners/systems will then process in a more timely fashion.
This is my view (with the information I have now). It may change.
But who knows what the risks involved are , changing from files to a WS message producing system ? And the risks for not changing ?
Start small and wind down the file producing system gradually if the future fulfills its promise.
At one time , I thought that databases would accomplish half of what's promised here (e.g.re-usable business logic using symbolic logic generators, remote transactions ) but it never did really take off. I can see a lot of the old ideas that fell by the way-side being re-visited.
I guess we are all part of a larger Experience Factory and are now in a different playing field. Wait and see what happens.

regards
[ May 21, 2003: Message edited by: HS Thomas ]
 
Lasse Koskela
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I agree. And we really are one big Experience Factory. In the end, most organizational/managerial "revelations" are actually adopted from observations of human behaviour in other contexts (e.g. Sun Zsu's The Art of War...).
Btw, I didn't mean that XML should not be used between internal systems -- just that XML is often unnecessarily generic (overhead) for the actual need.
 
HS Thomas
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At one time , I thought that databases would accomplish half of what's promised here (e.g.re-usable business logic using symbolic logic generators, remote transactions ) but it never did really take off. I can see a lot of the old ideas that fell by the way-side being re-visited.

Searching now, you find database that provide these capabilities and more.
How does a Java Designer handle a move from designing for a system that's network centric to one that is database-with-some-network capabilities centric ? For instance does this affect how he/she would use statics and the number of objects designed ?
Does this in turn affect whether you can use Design Patterns or which Design Patterns you use?
In turn, how is this going to affect how you develop with Web Services.
Does pushing the re-use boat out help one decide ?
Are you missing out on a mental paradigm shift ( a leap of faith , to me) if you stay database centric for a while ?

It'll be a great management team that takes its staff through ripple effects like this. Put a very large time-scale on this (5 years) and if your teams are still talking to each other you'll all have done a great job. (It's good to have all those emotional see-saws and life experiences (keeping emotionally and financially healthy) to see you thro' ).
Education and experience count but where do you start? I'll take a look at The Art of War, thanks Lasse.

regards
[ May 21, 2003: Message edited by: HS Thomas ]
 
Lasse Koskela
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Originally posted by HS Thomas:
How does a Java Designer handle a move from designing for a system that's network centric to one that is database-with-some-network capabilities centric ? For instance does this affect how he/she would use statics and the number of objects designed ?
Does this in turn affect whether you can use Design Patterns or which Design Patterns you use?
In turn, how is this going to affect how you develop with Web Services.

I wouldn't say it affects the use of design patterns -- they're used as before within a node in the network (few design patterns are related to network deployment).
All this web services stuff isn't really anything new in the paradigm sense. It's new in the standardization sense but the same principles of distributed computing are very much the same as before.

Are you missing out on a mental paradigm shift ( a leap of faith , to me) if you stay database centric, for a while ?

By all means, stick with the old solutions if they work for you -- but be aware that alternatives exist. That's pretty much the mantra folks have been repeating for decades and it still holds.

Education and experience count but where do you start? I'll take a look at The Art of War.

Listen to the gurus on forums (javaranch, theserverside, javalobby). It has helped me a lot.
About The Art of War... Don't expect an easy read. The book is about war strategy, literally. However, the book has become a classic every business leader has (claimed to have) read because the principles of "whether to attack or evade" in a particular situation can be transferred to a competitive context. I've browsed the book, found it interesting, but haven't managed to sit down and really read it with thought.
 
HS Thomas
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Thanks Lasse .
Sound advice.
 
HS Thomas
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UML to BPEL4WS
And it seems not too long ago that we were discussing this, Lasse.
regards
[ September 27, 2003: Message edited by: HS Thomas ]
 
It is sorta covered in the JavaRanch Style Guide.
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