The Merger of Functional and Descriptive Languages.

So how do object-oriented methods and XML relate to one another? According to Rod Smith, vice president of Java Software at IBM, “… the entire success of a business in the online realm will hinge on its ability to exchange information seamlessly, regardless of where it’s generated or headed. E-business technologies such as Java and XML can enable these transactions to flow smoothly throughout the enterprise…” And according to Ajit Sagar, “Application server vendors who want to stay in the market over the next few years will have to clearly define the hooks for XML integration. XML is likely to become the lingua franca of Web data formatting and presentation in the years to come.” [i] In short, OOM provides the model and the connection to the functional software, while XML provides the structure and interchange format for the data itself. As object-oriented programmers spend more time on WWW applications and XML experts spend more time on developing functional systems, invariably their methods and language begin to merge.

            With the introduction of the XML Metadata Interchange specification (OMG Document ad/98-10-05, October 20, 1998) these two computer languages have begun to merge. XMI integrates UML, XML, and OMG’s Meta Object Facility/metadata repository standard. IBM and Unisys prototyped “round trip” engineering of UML models and XML using XMI and proved that it works without information loss. In short the XMI specification provides a complete specification for syntax and encoding needed to export and import meta-models. The XMI specification has two major components:

·        The XML DTD production Rules for producing XML Document Type Definitions for XMI encoded metadata. XMI DTDs serve as syntax specifications for XMI documents, and allow generic XML tools to be used to compose and validate XMI documents.

·        The XML Document production rules for encoding metadata into an XML compatible format. The production rules can be applied in reverse to decode XMI documents and reconstruct the metadata.

According to OMG, “There is a strong synergy between the OMG technologies and XML is a number of areas. OMG defines CORBA as the medium for interchange of data between objects that have network connectivity. XML represents a potential alternative interchange medium for cases where ORB to ORB (e.g., object request broker) connectivity is not possible. Furthermore, XML represents a possible medium for interchange of data between CORBA based systems and other systems.” Hence, the initial merger is complete: