Demand-driven object loading (example)

[Sai-Lai Lo]

Here is an example on how to use the dynamic object loading scheme I just
posted.

------------------- server.cc -------------------------------------
// Testing code: implementation of echo objects
//
//   interface Echo {
//        string echoString(in string mesg);
//   };

#include <iostream.h>
#include <string.h>
#include <echo.hh>


static BOA_var boa;

// implementation using inheritance skeleton
class Echo_i : public virtual _sk_Echo {
public:
  Echo_i() {}
  Echo_i(const omniORB::objectKey& key) : _sk_Echo(key) {}
  virtual char * echoString(const char *mesg);

};

char *
Echo_i::echoString(const char *mesg) {
  char *p = CORBA::string_alloc(strlen((const char*)mesg));
  strcpy((char *)p,(const char *)mesg);
  return p;
}


static
CORBA::Object_ptr
loader(const omniORB::objectKey& key)
{
  cerr << "Loader: create a new echo object." << endl;
  Echo_i* obj = new Echo_i(key);
  obj->_obj_is_ready(boa);
  return obj->_this();
}


int
main(int argc, char **argv)
{
  CORBA::ORB_var orb = CORBA::ORB_init(argc,argv,"omniORB2");
  boa = orb->BOA_init(argc,argv,"omniORB2_BOA");

  omniORB::loader::set(loader);

  CosNaming::Name use_name;
  
  Echo_i *myobj = new Echo_i();
  myobj->_obj_is_ready(boa);

  {
    Echo_var myobjRef = myobj->_this();
    CORBA::String_var p = orb->object_to_string(myobjRef);
    cerr << (char*)p << endl;
  }

  // Delete the object, let the loader reinstantiate the object when the
  // client calls it.
  myobj->_dispose();

  boa->impl_is_ready();

  return 0;
}

-------------------------------------------------------------------------
------------------- client.cc -------------------------------------------
// Testing code: client of echo objects
//
//   interface Echo {
//        string echoString(in string mesg);
//   };
//

#include <iostream.h>
#include <echo.hh>

int
main (int argc, char **argv) 
{
  CORBA::ORB_ptr orb = CORBA::ORB_init(argc,argv,"omniORB2");

  CORBA::Object_var obj;

  if (argc == 2) {
    obj = orb->string_to_object(argv[1]);
    if (CORBA::is_nil(obj)) {
      cerr << "Cannot convert stringified IOR to an object reference."
	   << endl;
      return 1;
    }
  }
  else {
    cerr << "usage: client <stringified IOR>" << endl;
    return 1;
  }

  Echo_var e = Echo::_narrow(obj);
  if (CORBA::is_nil(e)) {
    cerr << "Can't create proxy.\n" << endl;
    return 1;
  }

  if (e->_non_existent()) {
    cerr << "Object does not exist.\n" << endl;
    return 1;
  }

  try {
    int loopcount = 10;
    while (loopcount--) {
      char * echostr;
      echostr = e->echoString((char *)"abcde");
      cerr << "reply " << echostr << endl;
      if (strcmp((const char *)echostr,"abcde")) {
	cerr << loopcount << " : echo string differs ('" << "abcde', '" 
	     << (char *)echostr << "')" << endl;
	break;
      }
      CORBA::string_free(echostr);
    }
  }
  catch (const CORBA::COMM_FAILURE&) {
    cerr << "Caught COMM_FAILURE exception. Exit." << endl;
  }

  return 0;
}

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