Modeling Approach Of Software Executable Models Based On OOCPN

With software applications penetrating into more and more areas, software systems have become larger and much more complex, which has made development of software even harder and has brought about increasing potential problems embedded in systems. Defects at early stage of design would seriously hamper the following development, application and maintenance of systems. Therefore, if the errors and defects were detected in time during early stage, the efficiency of designing and developing software systems would achieve remarkable increases at much smaller expenses. Thus, modeling and validating of software systems has been a research focus in software engineering.Traditional modeling approaches for software system mainly includes mathematic modeling method, structured modeling method, information modeling method, object oriented modeling method, and so on. Those approaches played a role in software development history There, however, still exist drawbacks in those modeling methods. The abstractness of mathematic modeling approach hampers analysis, development and design of the system. Adopting structured modeling method always results in problem space inconsistent with solution space. Information modeling method concentrates on conditions rather than objects, which puts limitations on established models. Although object oriented method supports software system modeling well, it is not formalized enough to analyze and verify models. Every improvement in software developing method has enhanced the abstractness of software system. Thus, enhanced abstractness has reduced specific information the system involves and has eliminated limitations of the system, which improves the adjustability and generalization of the system. Enabling abstract models to simulate practical application system in a manifesting way and detecting drawbacks in system design at early stage can significantly enhance productivity and quality of software system. For this reason, establishing highly visualized and executable models improves software development approaches.Much work has been done in research on software modeling approach, and achievement has been obtained. There still exist several drawbacks. Current research is impeded by low performability. The simulation of the reality system should be enhanced. Adopting traditional methods, it is hard to detect defects and flaws of the design. Based on previous achievements, the paper, in view of the drawbacks of recent research, started from visualized and executable models to explore and elaborate on software system modeling based on combination of Object Oriented technology and Petri Nets, and proposed solutions. The major work and contribution of the paper unfold as follows.The paper analyzed and summarized traditional modeling methods, based on which the paper proposed four approaches of combining Object Oriented technology and Petri Nets to establish executable models for software systems, and classified the approaches into three categories. The approaches are categorized as object oriented technology embedded with Petri Net, Petri Net embedded with object oriented technology, and those two embedded into each other. Furthermore, the paper put forward formal definition and semantic explanation of OOPN and performed an in-depth analysis of object oriented feature of OOPN.The paper proposed modeling method based on OOPN interaction behaviors on graphic interface. In view of users’habitual operations on graphic interface, the paper, firstly, determined operating objects on interface, gave formal descriptions of their properties and behaviors using OOPN, and formed object sub nets. Secondly, the paper analyzed relations within objects and defined behavioral correlations and associations within object sub nets. The behavioral correlations and associations of behaviors are classified as sequence, synchronization, selection, concurrency and mutual exclusion. Thirdly, the paper based on system requirement analysis assembled and integrated subnets and their correlations, and proposed executable model of the system. Finally, the paper, in accordance with execution semantics and conditions of transition firing of OOPN, checked possible execution processes and verified correctness and applicability of the model.The paper came up with an improved OOPN, expanded correlations within sub nets and made it form a virtual net structure. Thus, the paper proposed principles of stratification and reduction rules of OOPN and verified the applicability of reduction rules. In addition, the paper suggested algorithm for deadlock marking detection of object sub nets and OOPN and applied it into practical use. By application in cases, stratification method, reduction rules and deadlock marking detection algorithm are verified and validated.Summarizing drawbacks in modeling based on OOPN, the paper put forward the formal description of fundamental communication protocol on the basis of Object Oriented Colored Petri Nets which combines object oriented technology with colored petri nets. Adopting such approach, the paper, following an example of a simple communication protocol, made use of CPNTools and established an automatic executable model. Then, the paper checked the correctness of the protocol and verified properties of the model by simulating execution. Meanwhile, the paper, making use of the results of the simulated execution of executable models analyzed and evaluated the communication performance of the protocol.The paper proposed new penetrating method for in-depth researching on software system modeling, which will, in both theoretical and practical way, help detect problems at early stage of designing and developing software system and enhance efficiency as well as reliability of design and development. Nevertheless, there still exist defects in the proposed approach. Much more is to be done to improve and optimize the method. By combination with popular modeling language, namely UML and establishment of a mechanism for describing models regardless of platform, the proposed approach will play significant role in designing and developing software systems. More case studies and property research of models are necessary to enhance the efficiency and quality of software system development and design.