Hi, Completely agree with your thoughts that businesses goes through a strict legal process on contract formation and transaction execution. The point with loosely coupling, however, is that these strict legal process is ongoing. IMHO, I don't think loosely coupling in SOA context necessitates dynamic search for the "best service" on each invocation of a process as I've seen on some web service demos. IMO, loosely coupling implies that a business user is able to define and redefine a process - which involves selection of services. As you pointed out, each defined process and their corresponding services are well defined.
Cheers, H.Ozawa Mike Glendinning wrote: > > To help stop this list degenerating into "Steve Jones against the > world", let me just agree with Steve here and further emphasise this > last point, which is a current concern of mine. > > Most of what goes on in business today is actually quite "tightly > coupled". > > In particular, buying and selling stuff (that is, the general > commercial trading activity of most businesses) goes through a strict > legal process of contract formation and transaction execution between > two parties. This involves well-defined legal concepts such > as "invitation to treat", "offer", "acceptance" and "consideration". > > Businesses define the rules for such things very precisely and this > applies equally to B2B and B2C purchasing scenarios as well as > transactions of both small and large monetary value. > > When negotiating these contracts and executing transactions, businesses > pay close attention to the details of what is being said. Anything > proposed by the other party is subject to detailed scrutiny before > being incorporated into the contract terms or allowed to affect the > outcome of a transaction. > > A business would never knowingly execute a contract or transaction, > parts of which it did not understand. Of course consumers sometimes do > (for low-value items) but only out of laziness (and perhaps stupidity) > in reading the "small print" and this does cause them problems in > practice. > > In designing computer systems, we generally try to model the behaviour > of the business as closely as possible. It is arguable, therefore (and > strongly, in my view) that any computer system designed to automate > this kind of commercial business activity must be similarly "tightly > coupled". > > This would mean that messages exchanged as part of a transaction must > be fully understood by both parties, and rigorously checked for > accuracy and completeness. Each party must be sure that nothing is > being said by the other party that may materially affect [in the legal > sense] the outcome of the transaction. > > Both the messages themselves and their interactions must therefore be > carefully designed to align properly with the commercial [legal] > aspects of the activity they are automating. > > Of course this doesn't prevent the message definitions from > being "extensible" in any way, but it does suggest that the current > vogue for loose message definition, sloppy parsing and ignoring data > you don't understand may not be appropriate in many business contexts. > > -Mike Glendinning. > > P.S. Businesses do, of course in some areas and industries make use of > intermediaries to reduce the effects of this "tight coupling" (for > example in the various B2B purchasing exchanges), but even so both legs > of such brokered transaction remain tightly coupled as I have described. > > > >
