Andreas Vogel

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Top Stories by Andreas Vogel

Two months ago (JDJ, Vol.2, Iss. 2), Ellen Siegel gave a very nice introduction to CORBA from a Java point of view. This article is focused on a more specific topic which often occurs to newcomers to the CORBA world: How do I discover the objects I want to use? Identification of an Object To answer this question, we must first establish how we identify an object. Similarly to Java, CORBA identifies objects by an object reference. An object reference is an opaque datatype which contains all the information needed to successfully invoke an operation on the object (even when the object has been relocated). The CORBA 2.0 Specification defines Interoperable Object References (IORs) which enable object identification across ORB boundaries. In the Java language mapping, an IDL-defined interface is mapped to a Java interface. A client declares a variable of the Java interface... (more)

CORBAnet Turns One

OMG's Internet Inter-ORB Protocol (IIOP) has developed quite a career in a short space of time. Its specification was released in late 1994 as part of OMG's CORBA2.0 specification. Only a few months later, the first ORBs implemented the protocol and interoperability between various ORBs was demonstrated to the world during Object World West in mid-1995. In mid-1996, Netscape declared its support for IIOP as the Internet protocol for distributed applications. Now, everyone seems to be jumping on the IIOP bandwagon. This popularity demonstrates the need for a standardised protocol ... (more)

Distributing Events

The notion of events is quite overloaded and various event models have been suggested, standardized and implemented. In this article, I explain the event models in Java, CORBA and ORBs: JavaBeansª and Java events Kona InfoBus CORBA Event Service Visibroker's Event Handlers I also show how Java events can be distributed using CORBA. JavaBeans Events One of the major core features of JavaBeans is an event. The event model is based on JDK 1.1 extensions to the package java.util. These extensions are the class EventObject, the interface EventListener and the exception TooManyListenersE... (more)