Instance Pointcuts: Selecting Object Sets Based on Their Usage History

At runtime, how objects have to be handled frequently depends on how they were used before. But with current programminglanguage support, selecting objects according to their previous usage patterns often results in scattered and tangled code. In this study, we propose a new kind of pointcut, called Instance Pointcuts, for maintaining sets that contain objects with a specified usage history. Instance pointcut specifications can be reused, by refining their selection criteria, e.g., by restricting the scope of an existing instance pointcut; and they can be composed, e.g., by set operations. These features make instance pointcuts easy to evolve according to new requirements. Our approach improves modularity by providing a fine-grained mechanism and a declarative syntax to create and maintain usage-specific object sets.