Distributed Systems Development - Autonomics Development: A Domain-Specific Aspect Language Approach - page 27

import DateApp.∗;
import org.omg.CosNaming.∗;
import org.omg.CORBA.∗;
public class DateClient {
static Date dateImpl;
public static void main(String args[]) {
try {
// create and initialize the ORB
ORB orb = ORB.init(args, null);
// get the root naming context
org.omg.CORBA.Object objRef =
orb.resolve_initial_references( "NameService" );
// Use NamingContextExt instead of NamingContext. This is
// part of the Interoperable naming Service.
NamingContextExt ncRef = NamingContextExtHelper.narrow(objRef);
// resolve the Object Reference in Naming
String name = "Date" ;
dateImpl = DateHelper.narrow(ncRef.resolve_str(name));
System.out.println( "Server's Date: " + dateImpl.getDate());
dateImpl.shutdown();
} catch (Exception e) {
System.out.println( "ERROR : " +e);
e.printStackTrace(System.out);
}
}
}
Figure 2.10. An example of a simple CORBA client. Code in
the shaded area implements Java's CORBA framework.
by allowing for the discovery and spontaneous interaction between services in a
network.
AsmentionedinSection2.3, in order to reduce the programmers' burden,
RPC systems attempt to mask the differences between local and remote procedures
so that a remote procedure call is treated the same as a local procedure call.
Most distributed systems provide a unified view of objects in terms of their
location so that all objects are considered equal regardless of their physical loca-
tion. Indeed, many distributed systems, including most RPC systems, try and
mask the differences between local and remote objects by providing programmer
transparency.