Research And Implementation Of Generic Domain Modeling Tools Based On MOF

Modeling is becoming more and more important driven caused by the increasing complexity in software development. Model provides the overall view of the system, which is of great significance to understand the whole framework of the software and guide the direction of the development in a software project. GMT(Generic Modeling Tool)is a kind of modeling tool based on MOF. Not only is it widely available, but also has it a good ability of domain description. All the advantages are brought by the 2-level modeling and the support of aspect-oriented modeling.Commonly, we facing a complicated system, it is difficult for us to descript the system, we need a new mechanism. Firstly, according the question domain we create our own domain modeling language, and then we can begin to model domain model by means of this domain modeling language. This is the idea of 2-level modeling.MOF supports the 2-level modeling mechanism in theory studying and implementation. The central theme of the MOF approach to metadata management is extensibility. The aim is to provide a framework that supports any kind of metadata, and that allows new kinds to be added as required. In order to achieve this, the MOF has layered metadata architecture. The key feature of the MOF metadata architecture is the meta-metamodeling layer that ties together the metamodels and models. We apply the metadata architecture in GMT modeling domain. The MOF layer architecture provides the theoretical layer concept for 2-level modeling mechanism. We can depict 2-level modeling architecture with MOF layer.GMT support two stages modeling manner, the first is metamodeling higher progress than modeling, in this period, we set up concept entity in a special domain, thereby vocabulary will be formed. We also give the connection and constrain of these concept entities to be the domain metamodeling finally. The second, modeling which is worked out by meatmodeling, on basis of established connection in netamodeling and the process of modeling, it is for the product domain.A reasonable software system architecture should be composed of theOO(Aspect-Object)Module and the AOP(Aspect-Oriented Programming) Module, thus, the maintenance will be easy and the concept is in focus. The AOP method brought advantage in different periods and abstracted levels of software life cycle, it can be used both in question space (analysis, design and modeling) and solution space (implement and code). AOP has been upgraded to a higher level by GMT, it has been already used in analysis and design period. GMT supports AOP in metamodeling and modeling stages, in the former, we import the Aspect and Set components, in the latter, we model through many views using the Aspect component.GMT adopts triple system structure of which UI, operation logic and data memory dividedly, thus, realizes distributing work. There is a uniform interface between every layer, the upper layer only need transfer the lower one to perform interface service without concerning interface inside.UI provides the friendly modeling environment for users, it also shows the models defined before in graphic manner which composed of elements with their attributes and the connection between the elements. UI is realized completely by Java, mostly by Java Swing and JGraph.Operation logic layer sets between UI and data memory, it is realized by J2EE EJB, provides kinds of operation logic service for the upper layer, thus makes program more reused, portability and extended. There is also a memory interface in logic layer, which encapsulated the operation of database and document, thus insulates different data, shielded bottom detail. Upper one accesses bottom data by the interface, so the upper development turned simple, at the same time, coupling degree between each component turns lower.In operation logic layer, we implement the function of managing models, including many methods and a service interface for UI, mainly, we define some packages as follow.1.Data encapsulation package: encapsulating all the definitions of the entity, attribute and connection used in the progress of modeling and metamodeling.2.Database meta operation package: encapsulating the meta operation of the database.3.Model management meta operation package: providing the basal operations for managing model.Model management meta operation package and Database meta operation package are both design with middleware technology, we apply the JBoss web server and EJB to implement the whole operation logic layer in JBuider9.Data memory layer is the bottom in GMT framework, it works as model storage and takes charge of keeping the metamodel and model created in the period of metamodeling and modeling, including saving the model according to the semantic of model and metamodel, as well as saving the paradigm in XML, the paradigm is explained from the metamodel. The data layer adopted MySql database to realize the function. In concept design of the database, we divide the data memory to two periods: model storage and metamodel storage, then, design the memory concept of entity and connection that compsed the metamodel and model. In logic design of the database, we design a series of tables to storage the metamodel, because metamodel and model are constructed in different periods, we can use the same tables to save the model. The data stored in certain tables are in different category during different modeling phase, which can differentiate the meta-modeling and modeling. .