说明：  Aspect-oriented software development (AOSD) is emerging as a viable approach for allowing the separate expression of multiple concerns along with "weaving" technologies for knitting together these separate expressions into coherent systems. Thanks to its great promise as an approach to simplifying the development of complex systems, many expert observers view AOSD as a worthwhile successor to the prevalent object-oriented paradigm. In this new book, two AOSD experts apply theory to the practical realm of real-world development. They explain the different kinds of aspects, help the reader identify them, and provide guidance on successful design and implementation. The result is an applicable and easy-to-digest methodology for simplifying and optimizing the development of software systems.