Page History

...

Using WSDL 1.1, the policy-subject association usually takes the form of xml element attachment: A wsp:Policy element (the wsp prefix denotes the http://www.w3.org/2006/07/ws-policy^{Image Removed} namespace) is attached to a WSDL element such as wsdl:port. Alternatively, a wsp:PolicyReference elements is attached to a wsdl element. In that case, the actual wsp:Policy element can reside outside of the wsdl.
Note that subjects do not correspond to wsdl elements directly. Rather, they map to a set of wsdl elements (see below). For example wsdl:port, wsdl:portType and wsdl:binding elements together describe the endpoint as a subject.

...

In CXF, elements attached to a wsdl element are available as extensors in the service model representation of that wsdl element. wsp:Policy or wsp:PolicyReference elements can be obtained as extensors of type UnknownExtensibilityElement in which the element name matches that of the wsp:Policy or wsp:PolicyReference element. Note that these attached elements are not parsed when the service model is built.
With xml element attachment in WSDL 1.1, given a Message object, wsp:Policy elements attached to the endpoint or message subject can therefore be obtained by navigating the service model starting with the OperationInfo and/or EndpointInfo object stored in the message (or in the exchange).

The location of documents containing PolicyAttachment documents on the other hand needs to be made known to the framework. This can easily be achieved through configuration:

...

<bean class="org.apache.cxf.ws.policy.attachment.external.ExternalAttachmentProvider">
    <constructor-arg ref="cxf"/>
    <property name="location" value="org/apache/cxf/systest/ws/policy/addr-external.xml"/>
</bean>

The location of the document containing PolicyAttachments is specified in the form of a classpath resource or URL. Any number of external attachment providers can be specified. , see Specifying the Location of External Attachments.

PolicyAttachments are flexible w.r.t. the type of domain expressions. Domain expressions are used to identify entities such as endpoints, operations or messages with which a policy can be associated:

<wsp:PolicyAttachment>
    <wsp:AppliesTo> 
        <x:DomainExpression/> +
    </wsp:AppliesTo>
    (<wsp:Policy>...</wsp:Policy> | 
          <wsp:PolicyReference>...</wsp:PolicyReference>)
</wsp:PolicyAttachment>

...

The main purpose of these policy interceptors is to add further interceptors that are required to support the effective policy of the underlying message - even if that policy is not yet known at the time the policy interceptor executes (because the operation is not yet known at that time).
If the effective message policy is known, the assertions of its selected alternative are inserted into the message in the form of an AssertionInfoMap. This is a map, keyed by assertion type name, of collections of AssertionInfo objects, the latter being stateful (asserted/not asserted) representations of Assertion objects.
When the effective message policy is not known, not only the assertions for the selected alternative in the effective endpoint policy are included in the AssertionInfoMap, but also all assertions in all alternatives of all of the operation and message specific policies. Not all of these will be asserted at the end of the chain, but that is fine if it turns out the unasserted assertions apply to operation sayHi when in fact the chain has been processing the message for a greetMe request!

You can see how it designed on the following figure:

Image Added

Briefly, policy interceptors make following steps:

1. Check message property PolicyConstants.POLICY_OVERRIDE.
2. If PolicyConstants.POLICY_OVERRIDE contains policy, it will be taken for further processing.
3. If property is empty, policy will be asked from ServiceModel. Here CXF loads policies attached to WSDL or provided via Spring configuration.
4. If any policy on step 2 or step 3 is found, EffectivePolicy will be created. Appropriate WS-policies will be merged for the current message and built into Neethi Policy object.
5. All interceptors registered for result policy assertions will be added to message interceptor chain.

Policy Aware Interceptors

...