Notas de Aula - MAC 5759 - Sistemas de Objetos Distribuídos

Aula 13 - 23/4/2001

Interceptadores Portáteis (continuação)

• Interceptadores podem ser adicionados através da linha de comando ou através de código explícito na inicialização do ORB:
•  java -Dorg.omg.PortableInterceptor.ORBInitializerClass.com.x.Logging.LoggingService MyApp
• ORBInitializer
• public class LoggingService implements ORBInitializer {

     void pre_init( ORBInitInfo info ) {
         // Instantiate the Logging Service s Interceptor.
         Interceptor interceptor = new LoggingInterceptor();
         // Register the Logging Service s Interceptor.
         info.add_client_request_interceptor( interceptor )
         // cria um serviço qualquer e ...
         info.register_initial_reference("AService", aServiceImpl);
     }
     void post_init( ORBInitInfo info ) {
         // aqui pode-se chamar o resolve_initial_references ();
     }
 }
 
• interface org.omg.PortableInterceptor.ClientRequestInterceptorOperations
• receive_exception(ClientRequestInfo ri)

          Indicates to the interceptor that an exception occurred.
receive_other(ClientRequestInfo ri) (e.g. LOCATION_FORWARD, for retrying; asynchronous calls)
          Allows an Interceptor to query the information available when a request results in something other than a normal reply or an exception.
receive_reply(ClientRequestInfo ri)
          Allows an Interceptor to query the information on a reply after it is returned from the server and before control is returned to the client.
send_poll(ClientRequestInfo ri) (usado com o messaging system para ver se a resposta já chegou ou não)
          Allows an Interceptor to query information during a Time-Independent Invocation (TII) polling get reply sequence.
send_request(ClientRequestInfo ri)
          Allows an Interceptor to query request information and modify the service context before the request is sent to the server.
• ClientRequestInfoOperations
•  void add_request_service_context(ServiceContext service_context, boolean replace)

          Allows Interceptors to add service contexts to the request.
TaggedProfile effective_profile()
          Returns the profile that will be used to send the request.
Object effective_target()
          Returns the actual object on which the operation will be invoked.
TaggedComponent get_effective_component(int id)
          Returns the IOP.TaggedComponent with the given ID from the profile selected for this request.
TaggedComponent[] get_effective_components(int id)
          Returns an array of all tagged components with the given ID from the profile selected for this request.
Policy get_request_policy(int type)  (políticas são usadas por alguns serviços, p.ex. o de segurança).
          Returns the given policy in effect for this operation.
String received_exception_id()
          Returns the repository id of the exception to be returned to the client.
Any received_exception()
          Returns an any which contains the exception to be returned to the client.
Object target()
          Returns the object which the client called to perform the operation.

Bindings (Associações) e Repositório de Implementações

• Slides do Reverbel: Repositório de Implementações e Binding.
• Ler artigo do Michi Henning na página de leituras.