WSIT features are enabled and configured using a mechanism defined by the Web Services Policy Framework (WS-Policy) specification. A web service expresses its requirements and capabilities through policies embedded in the service’s WSDL description. A web service consumer, or client, verifies that it can handle the expressed requirements and, optionally, uses server capabilities advertised in policies.
Each individual WSIT technology, such as Reliable Messaging, Addressing, or Secure Conversation, provides a set of policy assertions it can process. Those assertions provide the necessary configuration details to the WSIT runtime to enable proper operation of the WSIT features used by a given web service. The assertions may specify particular configuration settings or rely on default settings that are predetermined by the specific technology. For instance, in the snippet shown below, the wsrm:AcknowledgementInterval and wsrm:InactivityTimeout settings are both optional and could be omitted. The following snippet shows WS-Policy assertions for WS-Addressing and WS-Reliable Messaging:
<wsp:Policy wsu:Id="AddNumbers_policy"> <wsp:ExactlyOne> <wsp:All> <wsaw:UsingAddressing/> <wsrm:RMAssertion> <wsrm:InactivityTimeout Milliseconds="600000"/> <wsrm:AcknowledgementInterval Milliseconds="200"/> </wsrm:RMAssertion> </wsp:All> </wsp:ExactlyOne> </wsp:Policy>
This snippet is valid in either a WSIT configuration file (wsit-package.service.xml) or in a Web Services Description Language (WSDL) file. This snippet is from the WSIT configuration file in the example, wsit-enabled-fromjava/etc/wsit-fromjava.server.AddNumbersImpl.xml.