Enterprise Service Bus Platform
Requirement for a Platform
The OsEra model is a logical architecture. It can not independently “execute.” An important feature of the MDA approach used by the DAT Team is separation of the concerns of the business from the concerns of the technology. The CIM and to some degree the PIM are independent of how the business needs will be met with technology. However, this does not eliminate the technology requirement or the requirement for superior technology design and implementation.
To become executable, a model requires a platform. The model is then executed on top of that platform using a variety of MDA techniques such as model augmentation, code generation, model interpretation, integration adapters, and component assembly. The details of these techniques will not be described here, but the end result of each is a model that was developed independent of technology becoming executable on a technical platform.
The platform is the specific set of standards and products that will host the components at runtime. It is expected that the target architectures will use one of the industry standard “containers” as the core platform, such as J2EE (WebLogic, Websphere, jBoss, etc.) or .NET, combined with the associated messaging, database, security and systems management infrastructure. Other, proprietary platforms can be supported as well.
The Role of the PSM in OsEra
There are various levels of scope and detail in a PSM depending on its purpose. A fully complete and detailed PSM would be capable of generating all or most of an application solution. While it is desirable for the the enterprise architectural approach to be able to support this level of detail, this is not the intent of EA or of OsEra. The purpose of a PSM in OsEra is to support simulation for architecture validation and to define middleware interfaces to support interoperability and integration. Of these, middleware interfaces are the primary external deliverable of the architecture. This specific use of MDA to support EA has been characterized by the enterprise as “Model to Integrate.” The PSM and PSI necessary to support “Model to Integrate” will fulfill the requirement for a “reference implementation” as defined in the SOW sample tasks.
Note that providers of components may well use MDA techniques that build directly from the OsEra models and add the detail required for a full implementation, but these implementation models are not “part of” OsEra directly. Later version of OsEra may well incorporate components for detailed implementation.
The Platform Specific Implementation (PSI)
The implementation artifacts provisioned from the PSM comprise the “platform specific implementation” for model to integrate. Depending on the platform these may be in the form of EJB archives or .NET bundles. The PSI is the actual generated artifacts ready for consumption by the platform as deployable packages. Typical PSI artifacts include; Java. C++ or Cobol code, Schema, interface definitions, XML files, SQL files, HTML, deployment descriptors, manifests, etc.