proposed resolution for issue 535

[Ken Laskey <klaskey@mitre.org>]

issue:

As expected, there was considerable discussion during the presentation at MITRE on how SOA is different, especially how it relates to OO.  Some points from emails, real-time discussions, and after discussions for consideration in expanding our discussion in the RM were noted.

proposed resolution:

Suggest incorporating some of the discussion of differences with OO by adding to lines 218-221 as follows:

Unlike Object Oriented Programming paradigms, where the focus is on packaging data with operations, the central focus of Service Oriented Architecture is the task or business function – getting something done. This distinction manifests itself in several ways:

• OO has intentional melding of methods to a given data object.  The methods can be thought of as a property of the object.  For SOA, one can think of the services as being the access to methods but the actual existence of methods and any connection to objects is incidental.
• To use an object, it must first be instantiated while one interacts with a service where it exists.
• An object exposes structure but no way to express semantics other than what can be captured as comments in the class definition.  SOA emphasizes the need for clear semantics.

Both OO and SOA are as much a way of thinking about representing things and actions in the world as these are about the specifics of building a system.  The important thing is understanding and applying the paradigm.  So the question is not “what is a service?” any more than it is “what is an object?”  Anything can be a service in the same way anything can be an object.  The challenge is to apply the paradigms to enhance clarity and get things done.  SOA provides a more viable basis for large scale systems because it is a better fit to the way human activity itself is managed – by delegation.

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Ken Laskey

MITRE Corporation, M/S H305     phone:  703-983-7934

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