Hi, Please find my comments inline.
On Thu, May 8, 2008 at 3:13 PM, Simon Laws <[EMAIL PROTECTED]> wrote: > In the SCA Policy framework spec there is a section that talks about > bindingType as it appears in the definitions.xml file(s). It says... > > 702 The bindingType element is used to declare a class of binding available > in a SCA Domain. It declares > 703 the QName of the binding type, and the set of intents that are natively > provided using the optional > 704 @alwaysProvides attribute. > > I hadn't noticed this before but the implication of these words appears to > be that a particular binding is not available for use in a domain unless > there is a > > 709 <bindingType type="NCName" > 710 alwaysProvides="listOfQNames"? > 711 mayProvide="listOfQNames"?/> > > element in the aggregate definitions.xml file. > > I guess this also applies to implementationType (which is defined in the > assembly spec) and interfaceType and databindingType (which aren't defned > in > the assembly spec so I just made them up here) > I am not sure if that's the implication. These defintions are a bit of meta-data about the binding-types and implementation-types in the domain and at the present moment this is restricted to the policy area i.e. the meta data today only talks about the intents supported in some way by an extension. I suppose in the future there could be a few other things that could get added as well. Upto now there no information there that is absolutely necessary to get an extension's basic functionality going. So if its not present nothing actually comes in the way with the basic functioning of the extension. However if you were to specify a policy intent which is inherently supported by the extension but the type info is missing, then the PolicyFwk will complain saying it does not have a PolicySet for this intent. The simple reason being the it does not know that the extension inherently supports this intent. > > Currently Tuscany uses the Java services approach to detect and load > extensions. If an extension is loaded it is available for use. We don't > check that bindingType, implementationType, etc is declared before making > an > extension available. > > As it happens some for our extensions include a defintions.xml file, for > example, > > http://svn.apache.org/repos/asf/incubator/tuscany/java/sca/modules/binding-ws-axis2/src/main/resources/org/apache/tuscany/sca/binding/ws/axis2/definitions.xml > . > And in this particular example a bindingType is defined. However this is > not > true of all of our extensions. > > Should we enforce the presence of a definitions.xml file in our extensions > and enforce that it contains an appropriate ?Type elemenent? On the face of > it there seems little benefit to doing this given our Tuscany specific > scheme for loading extensions. However it would tip our hat to the spec, > assuming we agree this is what the spec means, and give us a place to put > other extension configuration information it the need were to arise. > > Thoughts? > At the present moment I think its all very fine to load the extension even if the type info is not present. For instance if an extension has no intent that it supports inherently then there is no much need for the type info. However, if the scope of type info expands further to include more fundamental things that influence the basic functioning of the extension then we should probably enforce this for the simple reason that we cannot bring the extn up without its information. > > Regards > > Simon >
