Implementing the Assertor Interface - 7.3

With canAssert, the conduit/destination simply informs the framework if it understands a given type of assertions. In assertMessage on the other hand, the conduit/destination expresses support (or the lack thereof) for specific assertion instances. See Verification for a description of how this API is used by the verifying policy interceptors in the POST_STREAM or PRE_INVOKE phases. HTTPConduit is an exmaple of a policy aware Conduit. It supports assertions of type HTTPClientPolicy, which are represented in the runtime as JaxbAssertion<HTTPClientPolicy> objects. HTTPConduit also has a data member of type HTTPClientPolicy. It implements assertMessage as follows: for outbound messages, it asserts all JaxbAssertion<HTTPClientPolicy> that are compatible with this data member. For inboun d messages, all HTTPClientPolicy assertions are asserted regardless their attributes. The rationale for this is that the sematics of the HTTPClientPolicy assertion effectively does not mandate any specific action on the inbound message. Similary, on its inbound path, the HTTPDestination asserts all HTTPServerPolicy assertions that are equal to the HTTPServerPolicy assertion configured for the destination, and all assertions of that type on the outbound path.

class MyPolicyAwareConduit implements Assertor {
   static final QName MYTYPE = new QName("http://mycompany.com}", 
      "MyType"});

   public boolean canAssert(QName name) {
      return MTYPE.equals(name);
   }

   public void assertMessage(Mesage message) {
      AssertionInfoMap = message.get(AssertioninfoMap.class);
      ...
   }
}