System Object Model Programming Reference
Reprint Courtesy of International Business Machines Corporation, © International Business Machines Corporation
About This Book
SOM Kernel Reference
DSOM Framework Reference
A note on DSOM and CORBA
Distributed SOM (DSOM) is a framework which supports access to objects in a distributed application. DSOM can be viewed as both:
- an extension to basic SOM facilities
- an implementation of the "Object Request Broker" (ORB) technology defined by the Object Management Group (OMG), in the Common Object Request Broker Architecture (CORBA) specification and standard, Revision 1.1. The CORBA 1.1 specification is published by x/Open and the Object Management Group (OMG).
Note: Portions of this discussion of DSOM pertain to Workgroup DSOM only and are not supported by this Windows version of the product. References to topics such as ORB, CORBA, and selection of servers do not apply to this version. These discussions are presented here to provide a more complete understanding of DSOM in general.
One of the primary contributions of CORBA is the specification of basic runtime interfaces for writing portable, distributable object-oriented applications. SOM and DSOM implement those runtime interfaces, according to the CORBA specification.
In addition to the published CORBA 1.1 interfaces, it was necessary for to DSOM introduce several of its own interfaces, in those areas where:
- CORBA 1.1 did not specify the full interface (e.g., ImplementationDef, Principal)
- CORBA 1.1 did not address the function specified by the interface (e.g., "lifecycle" services for object creation and deletion)
- the functionality of a CORBA 1.1 interface has been enhanced by DSOM.
Any such interfaces have been noted on the reference page for each DSOM class.
A note on method naming conventions
The SOM Toolkit frameworks (including DSOM) and CORBA have slightly different conventions for naming methods. Methods introduced by the SOM Toolkit frameworks use prefixes to indicate the framework to which each method belongs, and use capitalization to separate words in the method names (for example, somdFindServer). Methods introduced by CORBA have no prefixes, are all lower case, and use underscores to separate words in the method names (such as, impl_is_ready).
DSOM, more than the other SOM Toolkit frameworks, uses a mix of both conventions. The method and class names introduced by CORBA 1.1 are implemented as specified, for application portability. Methods introduced by DSOM to enhance a CORBA-defined class also use the CORBA naming style. The SOM Toolkit convention for method naming is used for non-CORBA classes which are introduced by DSOM.