DSOM as a CORBA-compliant Object Request Broker

The Object Management Group (OMG) consortium defines the notion of an Object Request Broker (ORB) that supports access to remote objects in a distributed environment. Thus, Distributed SOM is an ORB. SOM and DSOM together comply with the OMG's specification of the Common Object Request Broker Architecture (CORBA).

Since the interfaces of SOM and DSOM are largely determined by the CORBA specification, the CORBA components and interfaces are highlighted in this section.

The CORBA specification defines the components and interfaces that must be present in an ORB, including the:

• Interface Definition Language (IDL) for defining classes (discussed in Chapter 4, "SOM IDL and the SOM Compiler").

• C usage bindings (procedure-call formats) for invoking methods on remote objects,

• Dynamic Invocation Interface and an Interface Repository, which support the construction of requests (method calls) at run time (for example, for interactive desktop applications), and

• Object Request Broker run-time programming interfaces.

SOM and DSOM were developed to comply with these specifications (with only minor extensions to take advantage of SOM services). Although the capabilities of SOM are integral to the implementation of DSOM, the application programmer need not be aware of SOM as the implementation technology for the ORB.

This section assumes some familiarity with The Common Object Request Broker: Architecture and Specification, Revision 1.1 (also referred to as "CORBA 1.1"). The specification is published jointly by the Object Management Group and x/Open. The mapping of some CORBA 1.1 terms and concepts to D SOM terms and concepts is described in the remainder of this section.