Chapter 6   The omniORB API

6.1   ORB initialisation options

6.2   Hostname and port

6.3   Run-time Tracing and Diagnostic Messages

CORBA::ULong omniORB::traceLevel = 1; // The default value is 1

$ eg2_impl -ORBtraceLevel 5

6.4   Server Name

CORBA::String_var omniORB::serverName;

6.5   GIOP Message Size

size_t omniORB::MaxMessageSize();

void omniORB::MaxMessageSize(size_t newvalue);

6.6   Object table size

6.7   POA request holding timeout

6.8   Obsolete Initial Object Reference Bootstrapping

  // IDL
  module CORBA {
    interface InitialReferences {
      Object get(in ORB::ObjectId id);
      // returns the initial object reference of the service
      // identified by <id>. For example the id for the
      // Naming service is "NameService".

      ORB::ObjectIdList list();
      // returns the list of service ids that this agent knows
   };
 };

1. Start omniNames for the first time on a machine (e.g. wobble):
   
   $ omniNames -start 1234
   
   
2. Add to omniORB.cfg:
   
   ORBInitialHost wobble
   
   ORBInitialPort 1234
   
   
3. All omniORB applications will now be able to contact omniNames.
   
   Alternatively, the command line options can be used, for example:
   
   $ eg3_impl -ORBInitialHost wobble -ORBInitialPort 1234 &
   
   $ eg3_clt -ORBInitialHost wobble -ORBInitialPort 1234

6.9   GIOP Lowest Common Denominator Mode

6.10   GIOP Requesting Principal field

6.11   Trapping omniORB Internal Errors

class fatalException {
public:
    const char *file() const;
    int line() const;
    const char *errmsg() const;
};

6.12   System Exception Handlers

6.12.1   CORBA::TRANSIENT handlers

1. When a cached network connection is broken while an operation invocation is in progress. The ORB will try to open a new connection at the next invocation.
   
   
2. When the proxy object has been redirected by a location forward message by the remote object to a new location and the object at the new location cannot be contacted. In addition to the CORBA::TRANSIENT exception, the proxy object also resets its internal state so that the next invocation will be directed at the original location of the remote object.
   
   
3. When the remote object reports CORBA::TRANSIENT.

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

static void installTransientExceptionHandler(void* cookie,
                                             transientExceptionHandler_t fn);

static void installTransientExceptionHandler(CORBA::Object_ptr obj,
                                             void* cookie,
                                             transientExceptionHandler_t fn);
  
static CORBA::ULong defaultTransientRetryDelayIncrement;
static CORBA::ULong defaultTransientRetryDelayMaximum;
}

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.
}

6.12.2   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);
}

6.12.3   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);
}

6.13   Location forwarding

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

1

omniORB is a class name if the C++ compiler does not support the namespace keyword.

2

This interface was first defined by Sun's NEO and is in used in Sun's JavaIDL.