The implementation of template method pattern by aspect based on configuration file

摘要

In the implementation of template method pattern by OOP (Object Oriented Programming), an abstract class defines the program skeleton of an algorithm and some common steps, deferring other steps to subclasses. Some steps are executed before the abstract method; other steps are executed after the abstract method. Subclasses extend this abstract class and implement the abstract method. When the pattern is implemented by AOP (Aspect Oriented Programming), common steps are defined in an aspect, when a join point is captured, some methods can be executed before or after it. This class doesn't need to extend one abstract class. The implementation is simple and noninvasive. But users need to know aspect language. This paper provides a novel method to implement this pattern: join point, after advice, and before advice are defined in a configuration file. On the basis of analyzing the AOP implementation of template method pattern, the paper discusses how to define these configurations. A program generates aspects based on the configuration file, then compiles, weaves. So users may use AOP implementation without knowing any Aspect.