MOP: Reliable Software Development using Abstract Aspects

Monitoring-Oriented Programming (MOP) is a formal framework for software development and analysis. It aims at reducing the gap between formal specification and implementation via runtime monitoring. In MOP, the developer specifies desired properties using definable specification formalisms, along with code to execute when properties are violated or validated, which can be used not only to report, but especially to recover from errors. The MOP framework automatically generates monitors from the specified properties and then integrates them together with the recovery code into the original system. Since the recovery code typically is executed infrequently and can be validated more easily than the actual system, MOP is expected to increase software reliability at little amortized runtime overhead. This paper presents MOP from a pragmatic, rather than foundational perspective, as an instance of aspect-oriented programming(AOP) where one defines abstract aspects using logics; one is relieved from providing unnecessary implementation details, because these are generated and integrated automatically. Existing AOP tools provide crucial support: an MOP frontend for Java, called JavaMOP and also discussed in the paper, is implemented using AspectJ. A series of examples illustrate the strengths of MOP from different perspectives.