Chapter 10: Enterprise Process Management

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Overview

As organizations move beyond a first application or first set of applications that are constructed and deployed on application servers, a new set of requirements emerges. These new requirements bring with them an additional set of questions, many of which translate into opportunities and requirements that need to be dealt with by the application server infrastructure. A push towards having a well-factored enterprise architecture of application components becomes necessary to deal with these more complex applications. As this occurs, additional heuristics and guidelines for application architecture are necessary.

Concurrent with understanding the architectural effects of broadening the use of applications servers comes a set of requirements around business logic and business logic factoring. WebSphere Application Server (WAS) provides a number of capabilities that address the challenges of reuse and flexibility.

Broadening the use of application servers in an organization brings to light a number of challenges, such as management of applications and operational requirements. Equally important, however, are the requirements that focus specifically on business logic and business logic factoring. Managing complexity demands that applications be structured for reuse and flexiblity. More large monolithic applications are not the goal. The development and operational costs of large monolithic applications are high. On the other hand, applications that are properly factored for reuse and that leverage the underlying constructs in the middleware will create a base from which more rapid and successful growth of application can occur.

A large servlet/JSP page application as a first application will probably contain a set of logic that is truly independent from the presentation aspects of the application. Often, the application will contain business logic that contains business rules and consists of a series of steps that accomplish a business task. A data-access layer is probably also part of the "first application", providing some encapsulation around interactions to a backend system. Succeeding applications may be created that require some of the same business rules, some of the same business logic, and access to the same business data.

Factoring applications such as these, leveraging session EJBs and entity EJBs, is a first step towards a stronger architecture for reuse. However, even applications that leverage EJBs can be somewhat brittle and monolithic in nature. Specific business logic and business rules may still be "locked" inside a larger component. Constructing new applications that reuse the business rules and many steps in a business logic flow might still prove difficult. Upfront architecture and planning is necessary to achieve the proper set of components. This architecture activity lays the foundation for scaling the usage of application servers in an organzation.

WAS provides a number of additional capabilities that address the challenges of reuse and flexibility and ease the development cost for process and flow-oriented applications.

This chapter will introduce the concept of Process Choreography and Business Rules as mechanisms for more efficiently creating, running, and changing business processes. These should be valuable tools to architects and developers of reusable components and well structured applications.