Chapter 4  omniORB configuration and API

4.1  Setting parameters

1. Command line arguments
2. ORB_init() options
3. Environment variables
4. Configuration file / Windows registry
5. Built-in defaults

4.1.1  Command line arguments

4.1.2  ORB_init() parameter

const char* options[][2] = { { "traceLevel", "1" }, { 0, 0 } }; 
orb = CORBA::ORB_init(argc,argv,"omniORB4",options); 

4.1.3  Environment variables

export ORBtraceLevel=10

4.1.4  Configuration file

traceLevel = 10

InitRef = NameService=corbaname::host1.example.com
        = InterfaceRepository=corbaloc::host2.example.com:1234/IfR

Note how command line arguments and environment variables prefix parameter names with `-ORB' and `ORB' respectively, but the configuration file and the extra argument to ORB_init() do not use a prefix.

4.1.5  Windows registry

4.2  Tracing options

4.2.1  Tracing API

namespace omniORB {
  CORBA::ULong   traceLevel;
  CORBA::Boolean traceExceptions;
  CORBA::Boolean traceInvocations;
  CORBA::Boolean traceThreadId;
};

namespace omniORB {
  typedef void (*logFunction)(const char*);
  void setLogFunction(logFunction f);
};

4.3  Miscellaneous global options

4.4  Client side options

4.5  Server side options

4.5.1  Main thread selection

namespace omniORB {
  void setMainThread();
};

4.6  GIOP and interoperability options

4.7  System Exception Handlers

4.7.1  Minor codes

try {
  ...
}
catch (CORBA::TRANSIENT& ex) {
  if (ex.minor() == omni::TRANSIENT_ConnectFailed) {
    // retry with a different object reference...
  }
  else {
    // print an error message...
  }
}

4.7.2  CORBA::TRANSIENT handlers

1. The client invokes on an object reference.
2. The object replies with a LOCATION_FORWARD message.
3. The client caches the new location and retries to the new location.
4. Time passes...
5. The client tries to invoke on the object again, using the cached, forwarded location.
6. The attempt to contact the object fails.
7. The ORB runtime resets the location cache and throws a TRANSIENT exception with minor code TRANSIENT_FailedOnForwarded.

namespace omniORB {
  
  typedef CORBA::Boolean (*transientExceptionHandler_t)(void* cookie,
                                                  CORBA::ULong n_retries,
                                                  const CORBA::TRANSIENT& ex);

  void installTransientExceptionHandler(void* cookie,
                                        transientExceptionHandler_t fn);

  void installTransientExceptionHandler(CORBA::Object_ptr obj,
                                        void* cookie,
                                        transientExceptionHandler_t fn);
}

CORBA::Boolean my_transient_handler1 (void* cookie,
                                      CORBA::ULong retries,
                                      const CORBA::TRANSIENT& ex)
{
   cerr << "transient handler 1 called." << endl;
   return 1;           // retry immediately.
}
 
CORBA::Boolean my_transient_handler2 (void* cookie,
                                      CORBA::ULong retries,
                                      const CORBA::TRANSIENT& ex)
{
   cerr << "transient handler 2 called." << endl;
   return 1;           // retry immediately.
}


static Echo_ptr myobj;

void installhandlers()
{
   omniORB::installTransientExceptionHandler(0,my_transient_handler1);
   // All proxy objects will call my_transient_handler1 from now on.

   omniORB::installTransientExceptionHandler(myobj,0,my_transient_handler2);
   // The proxy object of myobj will call my_transient_handler2 from now on.
}

4.7.3  CORBA::COMM_FAILURE

class omniORB {
public:

typedef CORBA::Boolean (*commFailureExceptionHandler_t)(void* cookie,
                                                CORBA::ULong n_retries,
                                                const CORBA::COMM_FAILURE& ex);

static void installCommFailureExceptionHandler(void* cookie,
                                             commFailureExceptionHandler_t fn);

static void installCommFailureExceptionHandler(CORBA::Object_ptr obj,
                                             void* cookie,
                                             commFailureExceptionHandler_t
                                             fn);
}

4.7.4  CORBA::SystemException

class omniORB {
public:

typedef CORBA::Boolean (*systemExceptionHandler_t)(void* cookie,
                                            CORBA::ULong n_retries,
                                            const CORBA::SystemException& ex);

static void installSystemExceptionHandler(void* cookie,
                                          systemExceptionHandler_t fn);

static void installSystemExceptionHandler(CORBA::Object_ptr obj,
                                          void* cookie,
                                          systemExceptionHandler_t fn);
}

4.8  Location forwarding

namespace omniORB {
  class LOCATION_FORWARD {
  public:
    LOCATION_FORWARD(CORBA::Object_ptr objref);
  };
};