Service Group Management facilitated by DSL driven Policies in embedded Middleware

Middleware by its very nature is fundamental to the functioning of systems as it provides the communication between software components. It is very much an underlying technology and is rarely visible to end users. As systems develop, certain domain semantics, provided by the domain experts, need to be injected into the behaviour of the underlying middleware, but in a controlled manner. The methods used to achieve this are often static in nature, wholly dependent on how they are implemented, deployed and managed. An increasingly popular way to manage this behaviour injection is through the use of policies, a technique used to govern defined rules, triggered by associated events, resulting in specific actions when certain conditions are encountered. Strong efforts have been made throughout the evolution of software development methods and programming languages to solve the lack of dynamicity which can arise through poor practices. Successive language based attempts to attain a higher level of abstraction in the notations used and techniques deployed have resulted in the re-discovery of Domain Specific Languages (DSL). This paper looks at injecting the dynamicity required in the management of service groups through a policy based DSL.