The Research Of Instantiation Of Design Pattern Based On XML Description

Design patterns and pattern-based software system development are advanced software technology. Software design patterns capture previous distill design experience. In the Object Oriented Programming developments, especially in the Component-based software development, how to effectively and accurately depict the design pattern is a major research subject nowadays. In this paper, we study the description of design pattern of software based on XML and the instantiation of design pattern based on this description.First of all, aiming at the disadvantages of Description of design pattern based on class diagram and notify (i.e. Description based on class diagram is not capable of depicting constraint conditions which are required in design pattern. The Description based on notify is not accurate enough in conveying its meanings. So it tends to result in misleading among the development staff) . a XML-based formal representation is introducted to describe design pattern solution. Depicting the design pattern by means of this description method can not only demonstrate the static structure information, but also accurately show the dynamic information, such as initialization and collaboration one in the design pattern. Moreover, not only is this new depicting method able to cover the shortages of traditional deign pattern in description of dynamic information, it can also conform numerous design patterns to the specifications, thus enabling them better understood ,recognized and managed by the users.Secondly, this paper is based on the proposed description of design pattern, analyzing the relationship between the design pattern and practicality design and the relationship between different design patterns. Furthermore, these relationships have been described by using Object Constraint Language. Basing on this, we put forward new instantiation methods of design pattern.Thirdly, the procedure for verifying the consistency between original software design patterns and the instantiated ones is also given. The combination of design pattern with component based soft development further improves the software quality and software development productivity.