Slides chapter 8
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The document discusses various modeling techniques used in software engineering analysis including use case diagrams, activity diagrams, data flow diagrams, state diagrams, class diagrams, and sequence diagrams. It provides examples of how each technique can be used to model a home security system called SafeHome that allows homeowners to configure, monitor, and interact with the security system.
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Slides chapter 8
- 1. Chapter 8 Analysis Engineering Software Engineering: A Practitioner’s Approach by Roger S. Pressman
- 2. Analysis Model Elements of the analysis model
- 4. Use-case Diagram Use-case diagram for surveillance function
- 5. Alternative Actions Can the actor take some other action at this point? Is it possible that the actor will encounter some error condition at this point? Is it possible that the actor will encounter behavior invoked by some event outside the actor’s control?
- 6. Activity diagram for Access camera surveillance—display camera views function
- 9. Guidelines Depict the system as single bubble in level 0. Carefully note primary input and output. Refine by isolating candidate processes and their associated data objects and data stores. Label all elements with meaningful names. Maintain information conformity between levels. Refine one bubble at a time.
- 10. Data Flow Diagram Context-level DFD for SafeHome security function
- 11. Grammatical Parse The SafeHome security function enables the homeowner to configure the security system when it is installed , monitors all sensors connected to the security system, and interacts with the homeowner through the Internet , a PC , or a control panel . During installation , the SafeHome PC is used to program and configure the system. Each sensor is assigned a number and type , a master password is programmed for arming and disarming the system, and telephone number(s) are input for dialing when a sensor event occurs. When a sensor event is recognized , the software invokes an audible alarm attached to the system. After a delay time that is specified by the homeowner during system configuration activities, the software dials a telephone number of a monitoring service , provides information about the location , reporting the nature of the event that has been detected . The telephone number will be redialed every 20 seconds until a telephone connection is obtained . The homeowner receives security information via a control panel, the PC, or a browser, collectively called an interface . The interface displays prompting messages and system status information on the control panel, the PC, or the browser window. Homeowner interaction takes the following form…
- 13. Level 2 DFD that refines the monitor sensors process
- 14. Control Flow Diagram State diagram for SafeHome security function
- 16. Identifying Analysis Classes External entities that produce or consume information Things that are part of the information domain Occurrences or events Roles played by people who interact with the system Organizational units Places that establish context Structures that define a class of objects
- 17. Class Selection Criteria Retained information Needed services Multiple attributes Common attributes Common operations Essential requirements
- 18. Identifying Classes reject: 1, 2 fail organizational unit; ee monitoring service accept: 1 fails external entity audible alarm accept occurrence sensor event reject: 3 fails thing telephone number reject: 3 fails thing master password reject: 3 fails not objects, attributes number, type accept thing (security) system reject occurrence installation accept external entity control panel accept external entity sensor reject: 1, 2 fail role; external entity homeowner Accept / Reject Classification Potential class
- 19. Class Diagram Class diagram for the system class
- 20. Class Diagram Class diagram for FloorPlan
- 21. CRC Modeling A CRC model index card for FloorPlan class
- 22. Class Responsibilities Distribute system intelligence across classes. State each responsibility as generally as possible. Put information and the behavior related to it in the same class. Localize information about one thing rather than distributing it across multiple classes. Share responsibilities among related classes, when appropriate.
- 23. Class Collaborations Relationships between classes: is-part-of — used when classes are part of an aggregate class. has-knowledge-of — used when one class must acquire information from another class. depends-on — used in all other cases.
- 24. Class Diagrams Top: Multiplicity Bottom: Dependencies
- 26. Identifying Events A use-case is examined for points of information exchange . The homeowner uses the keypad to key in a four-digit password . The password is compared with the valid password stored in the system . If the password in incorrect, the control panel will beep once and reset itself for additional input. If the password is correct, the control panel awaits further action.
- 27. State Diagram State diagram for the ControlPanel class
- 28. Sequence Diagram Sequence diagram (partial) for the SafeHome security function