Using SOM for Tool Integration

By [[]]

Abstract

IBM's System Object Model (SOM) is an object-oriented programming interface for building binary class libraries. When changes are made to a SOM class, client programs that use the SOM class will not need to be recompiled. The SOM Toolkit provides a set of frameworks for building object oriented applications. These include Distributed SOM, the Persistence Framework, the Replication Framework, and the Emitter Framework. In this paper, we discuss our experience using SOM to handle the control aspects of tool integration.

2.0 Introduction It is generally believed that software devel - oped using object-oriented techniques i s easier to use, maintain, and extend . SOM complements existing programming languages by providing a language-neutra l model for developing object-oriented appli - cations[1] . To use SOM, a developer defines the class interfaces in a language called Interface Definition Language (IDL) . The developer then implements the methods in any of the languages that are sup - ported by the SOM compiler. Finally, the classes are compiled into a dynamic lin k library (DLL) to be distributed to clients. Clients can use these classes directly o r can override existing methods to develop their own applications . As long as the clas s interfaces remain unchanged, a new DL L can be redistributed to clients without requiring them to compile their applications . This full backward binary compatibility of SOM is best demonstrated in th e building of the OS/2 Workplace Shell[4] . As the computer industry is moving toward distributed client-server systems, tools and applications have to interoperate in a heterogeneous environment. Existing integra -

tion techniques such as Dynamic Dat a Exchange[5] do not extend well into suc h distributed environments . The Object Request Broker (ORB), as defined by th e Object Management Group (OMG), provides mechanisms by which objects transparently make requests and receive responses. The ORB thus provide s interoperability between applications on different machines[2] . Distributed SOM (DSOM), which is built o n top of SOM, was developed to comply wit h the OMG's specification of the ORB[1 ] . DSOM makes the location of an object transparent to clients . This means that a client program will always use the same invocation to access an object regardles s of whether it is local or remote . Therefore a tool can use DSOM to interact with anothe r tool without knowing where the other too l is located . In this paper, we will look at how to use th e infrastructure in SOM to build and integrat e tools. We will then look at how these SOM - based tools can be easily used to compose new tools . Tool Composition refers t o the ability to build new tools by using existing tools . Finally, we will look at the notification aspects of tool communication.