CORBA 2.3.3 Getting Started Guide (NonStop CORBA 2.3.7+)

Most platforms do not ensure the availability, scalability, and transaction protection required for
OLTP applications and electronic commerce.
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Addressing the Challenges
Although these are formidable challenges, the distributed object architecture defined by the Object
Management Group® (OMG") in CORBA 2.3 goes a long way toward addressing the problems unsolved in
older object-oriented systems.
Since the definition of CORBA, numerous vendors have introduced Object Request Brokers (ORBs),
programming tools, and runtime environments for CORBA-compliant applications. In addition to offering
the standard set of ORB" functions and services, certain products have advanced the technology of
component-based development by addressing practical limitations of earlier object-oriented systems.
CORBA Defines Standard Interfaces and Services
The Common Object Request Broker Architecture (CORBA), illustrated in Figure 1.2, is defined by a
vendor consortium called the Object Management Group (OMG). In CORBA, an architectural component
called an Object Request Broker (ORB) transmits messages between clients and servers across a
heterogeneous network using the Internet InterORB Protocol (IIOP), which is the protocol standardized by
the OMG.
A client invokes objects in a server in either of two ways:
The Static Invocation Interface (SII) requires the client to know the object interface at compile time.●
The Dynamic Invocation Interface (DII) lets a client construct a request at run time if the object
interface is not known at compile time. The client can look up the interface for an object in a database
called the Interface Repository (IR).
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The server includes an object adapter. In NonStop CORBA, the object adapter is an implementation of the
CORBA Portable Object Adapter (POA), which provides an interface between the ORB and the object
implementations.
In addition to these components, CORBA specifies the following:
The OMG" Interface Definition Language (IDL)". You use IDL to describe the interface an object
presents to its clients, regardless of which programming language you use to implement the object or
clients.
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Mappings (also called bindings) from IDL to specific programming languages, such as C++ or Java.
When you compile an IDL specification, the IDL compiler generates language-specific stub files to
include in client programs and language-specific skeleton files to use as the basis for object
implementations.
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InterORB protocols (IOPs) for use in transmitting information among systems. IIOP is the Internet
protocol that the OMG defines as the standard for communicating across ORBs.
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Figure 1.2. Common Object Request Broker Architecture (CORBA)