The Modeling Of UML Diagrams Based On The Petri Net

As a well-defined and powerful graphical modeling language, UML cannot make formal analysis and verification because of lack of exactly semantic description. Nowadays, there are lots of study results of formalizing UML, but they are limited. The paper chooses the Petri net as the formal specification to convert UML model diagrams to the corresponding Petri net models on the basis of analyzing the features of the UML model diagrams. Because Petri net can also be expressed by graph, it can be directly converted from UML diagrams to be used as the tool of analysis and verification and the limitation of setting up models directly by formal methods is avoided which usually requires higher mathematical basis. Furthermore Petri net has a set of theoretical analytic methods and tools to remedy the model analysis and verification means of UML.The paper mainly puts forward the modeling methods of UML sequence diagram and class diagram based on the Petri net. For the UML sequence diagram, because of its limit expressive ability, we extend it with the power of modeling concurrence, choice, synchronization and so on, which are special in message-passing. And then nine conversion rules used to convert extended sequence diagram to Petri net are presented. For the class diagram, because it is the basis of each kind of dynamic behavioral diagrams in which the attributes and operations of the classes and the association between classes are defined, we choose Colored Petri net as the formal specification by analyzing the main elements of class diagram. We have analyzed the corresponding relation between the UML class elements and Colored Petri net elements. And specific form that class diagram should be satisfied before converting is given. Then we present the methods to convert UML class diagram to CPN at length. Therefore, the executable models of the two model diagrams are generated by conversion so that the formalization of the UML is achieved.