On Tue, 2006-06-27 at 09:00 +0100, Brian Hulse wrote: > I understand what you're saying, but there's a processing overhead > here. In your model, each module will winnow out the alternatives it > cannot support and pass on the result to the next. The problem with > this is that each will have to do an exhaustive search throughout the > whole policy tree, including, as you say, a complete match on what > could be very complex WS-SecurityPolicy assertions. This isn't > necessary, we only want a single supported alternative, we don't need > to process everything to get this.
So what algorithm are you suggesting? I guess an option would be to ask all the modules whether they can handle a specific alternative and then if not go to the next alternative? Even for that, the method indicated would have to be added to Module.java; the difference is how we call it. So, can we go ahead with adding this method? > In addition, I was being circumspect when I stated registration of > QNames ... this is a first stage pass of the winnow process, which is > high level and easy to do. After that, a higher level processing unit > (higher than the modules) would need to examine each alternative and > ask each module about its support statement on the assertions in its > domain. This two stage approach is what our code does and in doing so, > stops when a suitable alternative is found, rather than the exhaustive > approach you suggest. I understand that in small policies, with no or > simple choice, there is very little difference, but in the larger, > more complex cases, this will matter. See above; what you described is a good improvement of the above algorithm. In any case, it still requires the same method to be added to the Module class. > It should also be stated that there is still the possibility with your > model of a bad choice. If the model you choose is that domain A just > removes all alternatives it cannot support, and it leaves 2 > alternatives ... which does it use? It could select one that some > other domain could not support ... when in fact there is an > alternative which could pass everyone's tests. In this respect, you > have to have some central point of control, a Policy Decision Point, > and it can't be farmed out to the domains. Am I just confusing the > issue? No that cannot happen. If domain A leaves 2 alternatives, that means it CAN handle both. The policy decision point can pick any of those alternatives and then life must be good with that. Period. Sanjiva. --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
