Research On The Definitions And Realizations Of Joinpoint Based On Metadata

AOP aspect oriented programming is considered as a supplement for Object-oriented programming. Aspect-oriented programming consists of two parts: First, the basis program which achieve functional systems; Second,aspects code to achieve crosscutting concerns. AOP is now moving in the direction of the rapid development of practical, but it faces two problems to be solved, "the Structural conflict" and "the Behavioral conflict." In this paper, I give a solution for "the Structural conflict", use JAVA complete the metadata-based support tools of the connection point, and make the support tools integrated to eclipse in the form of plugins, to ensure the practicality of the solution."The Structural Conflict" is also called "fragile pointcut problem." Mainly about two aspects: First, the unexpected loss of connections point. When the physical information of the basis program changes, the entry point of the aspect code can not find the corresponding information, so the matched point is not match because of the changed physical information. Second, the unconscious connection point matching problem. When the physical information of the basis program changes, the matched entry point of the aspect code can not find the correspond interface of the basic program, but the connection point that programer do not want to match may match with the changed physical information. These two problems were mainly due to aspects code are close with the basic program, the connection point model of the aspect code can not fit the evolution of the basic program.This paper gives the solution of structure of conflict. In this paper, we add a Conceptual on the aspect code and the basic program, to achieve the decoupling between base program structure with the definition of JoinPoint. The concept mode in the conceptual express by the xml and the logic information of the basic program use Java Annotation mark. The pointcut of the aspect code is also defined by the corresponding logic information of the basic program and concept mode consist of the physical information and logic information and the mapping of the basic program.This paper introduces the JoinPoint based on the definition of the metadata methods, to get the mappig information between the basic program structure of the physical information and logical information of JoinPoint in the conceptual model. This paper gives a good solution on the structure confict problem of the AOP application program.