Feature Composition Edge Cases

ref: http://www.w3.org/TR/2004/WD-wsdl20-20040803/#Feature_composition_model

Does our feature composition model capture all possible cases? I am not
sure. Here is a sample edge case,

<interface name="Bank">
    <!-- All implementations of this interface must be secure -->
    <feature uri="http://example.com/secure-channel"
             required="true"/>
    ..
</interface>

<interface name="OpenBank" extends="Bank">
    <!-- we don't give a damn -->
    <feature uri="http://example.com/secure-channel"
             required="false"/>
    ..
</interface>

According to Interface Component,

"{features}	= The set of Feature components corresponding to the feature
element information items in [children], if any, plus the set of Feature
components in the {features} property of the Interface components in
{extended interfaces}, if any."

According to our equivalence rules, feature declared in Bank interface is
not equivalent to the feature declared in Open Bank interface. Because, the
value of {required} property is different. If these two feature components
are present in interface component.{features}, what is the net effect?
Secure channel is an optional feature! That confuses me. Please revisit our
feature composition model and flush out all such edge cases.

Also, shall we provide a special rule for computing the equivalence of
feature components?

Regards,
Asir S Vedamuthu
asirv at webmethods dot com
http://www.webmethods.com/

Received on Tuesday, 24 August 2004 02:32:52 UTC