Aop with Design Patterns as Meta-programming Operators

AOP (aspect-oriented programming) is an important new software construction methodology because it allows to specify parts and behaviors of components in a view-based way, i.e. with aspects. While these aspects can be speciied independently from each other, a weaver tool combines them to the nal form of the component. This yields software that is better readable (since speciications are modular) and better reusable (since aspects can be re-combined). We show for an object-oriented setting, how AOP can be performed without weaver tool. The weaving of an aspect into a component (here a class) can be described by an application of a design pattern. Hence design patterns can be used as powerful meta-programming operators that modify components in order to introduce aspects of computations, and to combine several aspects of a component into a single representation. Additionally, the composition can be checked with standard program analysis techniques whether it is harmless, i.e. whether resulting classes still can substitute their unmodiied versions. This immediately has the consequence that the development of a speciic weaver tool is not necessary.