AspectJ does not provide a mechanism to hide implementation details from advice. As a result, aspects are tightly coupled to the implementation of the code they advise, while the behaviour of the base code is impossible to determine without analysing all advice that could modify its behaviour.The concept of <i>open modules</i> is proposed by Aldrich to… (More)
These notes are an introduction to .QL, an object-oriented query language for any type of structured data. We illustrate the use of .QL in assessing software quality, namely to find bugs, to compute metrics and to enforce coding conventions. The class mechanism of .QL is discussed in depth, and we demonstrate how it can be used to build libraries of… (More)
In aspect-oriented programming, one can intercept events by writing patterns called <i>pointcuts</i>. The pointcut language of the most popular aspect-oriented programming language, AspectJ, allows the expression of highly complex properties of the static program structure.We present the first rigorous semantics of the AspectJ pointcut language, by… (More)
A wealth of recent research involves generating program monitors from declarative specifications. Doing this efficiently has proved challenging, and available implementations often produce infeasibly slow monitors. We demonstrate how to dramatically improve performance -- typically reducing overheads to within an order of magnitude of the program's normal… (More)
A trace monitor observes the sequence of events in a system, and takes appropriate action when a given pattern occurs in that sequence. Aspect-oriented programming provides a convenient framework for writing such trace monitors. We provide a brief introduction to aspect-oriented programming in AspectJ. As-pectJ only provides support for triggering extra… (More)
Many tasks in source code analysis can be viewed as evaluating queries over a relational representation of the code. Here we present an object-oriented query language, named .QL, and demonstrate its use for general navigation , bug finding and enforcing coding conventions. We then focus on the particular problem of specifying metrics as queries.
AspectJ's pointcut language is complex, yet often not expressive enough to directly capture a desired property. Prolog has been suggested as an alternative, but Prolog queries may not terminate, and they tend to be verbose. We solve expressiveness, termination and verbosity by using <i>Datalog</i> plus <i>rewrite rules</i>.
We give an introduction to aspect-oriented programming from the viewpoint of data refinement. Some data refinements are conveniently expressed via aspects. Unlike traditional programming language features for data refinement , aspects conceptually transform run-time events, not compile-time programs.
Aspect-oriented programming languages provide advice to modify the behavior of programs. Some current languages, notably AspectJ, provide few limitations on advice, so new advice can change the behavior of existing programs without any restrictions. Changes to the base code can also affect the behavior of existing advice in an unexpected manner. Open… (More)