Interceptors
Interceptors are an important concept of the xdi2-messaging and xdi2-server components. They are used as an extensibility mechanism to augment the functionality of the server. For example, they can be used to implement security checks or trigger actions when certain events occur. They may also contribute data to the result of a message, however this is not their main purpose.
The interceptors of the xdi2-messaging component can augment the functionality of messaging targets. The EndpointServletInterceptor of the xdi2-server-logic component can augment the functionality to the endpoint servlet.
A single class can implement multiple interceptor interfaces. For example, an interceptor might need to be called before each message is executed, and when an operation is executed on an XDI statement or an XDI address. Therefore, this interceptor would implement the MessageInterceptor and the TargetInterceptor interfaces.
- xdi2.messaging.target.interceptor.MessagingTargetInterceptor: Interceptor that is executed when a messaging target is initialized and shut down.
- xdi2.messaging.target.interceptor.MessageEnvelopeInterceptor: Interceptor that is executed before and after a message envelope is executed, as well as when an exception occurs while executing the message envelope.
- xdi2.messaging.target.interceptor.MessageInterceptor: Interceptor that is executed before and after a message is executed.
- xdi2.messaging.target.interceptor.OperationInterceptor: Interceptor that is executed before and after an operation is executed.
- xdi2.messaging.target.interceptor.TargetInterceptor: Interceptor that is executed when an operation is executed on an XDI statement or an XDI address.
- xdi2.messaging.target.interceptor.ResultInterceptor: Interceptor that is executed on a message result after a message envelope has been executed.
- xdi2.server.interceptor.EndpointServletInterceptor: Interceptor that is executed when the EndpointServlet is initialized, destroyed, or when it receives an incoming HTTP request.
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