SSTEM SYSTEM VENT MUTING 匙EA 2. BUTTON RELEASE recerved 2. BUTTON PUSH onds aher e MUTING FIGURE 90.7 RBS object interface specificatio For each object there is an object interface specification(as shown in Fig. 90.7)which shows the public and private interfaces to an object. An event list is also associated with this specification; it shows how the object will respond to external stimuli. a hierarchy of transformation diagrams is associated with each object specification(as shown in Fig. 90. 8 for the RBS). This diagram defines all of the functions or"methods"which the object performs Some behavior may be expressed by means of a state transition diagram(Fig. 90.9 Implementation Modeling Two principal activities must be accomplished in transitioning from the essential to the implementation model. First, all of the methods and data encapsulated by each object must be mapped to the implementation environ- ment. This process is illustrated in Fig. 90.10. Second, all of the details which were ignored in the essential model (such as user interfaces, communication protocols, hardware limitations, etc. )must now be accounted for Each component of the essential model must be allocated to hardware processors. Within each hardware processor, allocation must be continued to the task level. Within each task, the computer program controlling that task must be described. This latter description is accomplished by means of a module structure chart. As illustrated in Fig. 90.11 for one component of the RBS, the module structure chart is a formal description of each of the computer program units and their interfaces. CASe Tools The term computer-aided software engineering(CASE) is used to describe a collection of tools which automate all or some of various of the software engineering life cycle phases. These tools may facilitate the capturing, tracking and tracing of requirements, the construction and verification of essential and implementation models and the automatic generation of computer programs. Most Case tools have an underlying project repository which stores project-related information, both textual and graphical, and uses this information for producing CASE tool features may include trac Maintenance of all project-related information · Model verification Facilitation of model validation e 2000 by CRC Press LLC© 2000 by CRC Press LLC For each object there is an object interface specification (as shown in Fig. 90.7) which shows the public and private interfaces to an object. An event list is also associated with this specification; it shows how the object will respond to external stimuli. A hierarchy of transformation diagrams is associated with each object specification (as shown in Fig. 90.8 for the RBS). This diagram defines all of the functions or “methods” which the object performs. Some behavior may be expressed by means of a state transition diagram (Fig. 90.9). Implementation Modeling Two principal activities must be accomplished in transitioning from the essential to the implementation model. First, all of the methods and data encapsulated by each object must be mapped to the implementation environ￾ment. This process is illustrated in Fig. 90.10. Second, all of the details which were ignored in the essential model (such as user interfaces, communication protocols, hardware limitations, etc.) must now be accounted for. Each component of the essential model must be allocated to hardware processors. Within each hardware processor, allocation must be continued to the task level. Within each task, the computer program controlling that task must be described. This latter description is accomplished by means of a module structure chart. As illustrated in Fig. 90.11 for one component of the RBS, the module structure chart is a formal description of each of the computer program units and their interfaces. CASE Tools The term computer-aided software engineering (CASE) is used to describe a collection of tools which automate all or some of various of the software engineering life cycle phases. These tools may facilitate the capturing, tracking and tracing of requirements, the construction and verification of essential and implementation models and the automatic generation of computer programs. Most CASE tools have an underlying project repository which stores project-related information, both textual and graphical, and uses this information for producing reports and work products. CASE tool features may include: • Requirements capture, tracing, and tracking • Maintenance of all project-related information • Model verification • Facilitation of model validation FIGURE 90.7 RBS object interface specification