WHAT'S NEW IN CORBA 3
CORBA, already the architecture of choice for enterprise integration, gains new capabilities with the arrival of CORBA 3. The additions fall into four categories:- CORBAcomponents
- Java and internet integration
- Quality of Service
- Messaging
CORBAcomponents: The CORBAcomponents specification makes CORBA easier to use for every link of the software chain: Programmers, Software Providers, Systems Administrators, and End-Users. It defines a container development and runtime environment which is persistent, transactional, and secure; the container also incorporates an installation engine which, working with the newly defined multi-platform distribution format, enables CORBAcomponents to be purchased off-the-shelf, installed, and configured for a particular need. Providing more than the Enterprise Java Bean environment, the CORBAcomponent container also accepts EJBs which then plug-and-play with CORBAcomponents written Java and other CORBA-enabled languages including C++. Event channels and interface connections allow multiple components installed in a container to merge into assemblies which provide a suite of services to the user.
Java and Internet Integration: Besides the EJB integration provided by CORBAcomponents, CORBA 3 also defines a Java-to-IDL language mapping. The reverse of the usual IDL-to-Language mapping which enables language code to invoke CORBA stubs or be called by CORBA skeletons, this mapping instead generates IDL files from Java objects which lets them play in a CORBA distributed system. So, these Java objects can be called by clients written in other languages, or re-implemented in languages other than Java.
Quality of Service: QoS - whether done via priority setting or use of realtime implementations - is how an enterprise copes with unexpected demand in the face of limited resource. CORBA 3 provides a number of places where priorities can be set, and defines a new specification for realtime CORBA.
Messaging: During the past several years, the distributed computing world has defined sophisticated messaging and asynchronous invocation modes for distributed computing. OMG has applied this experience to the new CORBA messaging specification which adds both callback and polling mode asynchronous invocations to CORBA, along with a new time-independent invocation mode which allows invocation and response between a client and CORBA object which may not be running or even attached to the network simultaneously.