2 Objectives■ Understand the rules and style guidelines for activity diagrams.■ Understand the rules and style guidelines for use cases and use case diagrams.■ Understand the process used to create use cases and use case diagrams.■ Be able to create functional models using activity diagrams, use cases, and usecase diagrams.■ Become familiar with the use of use case points.
3 Business Process Modeling with Activity Diagrams Elements of an Activity DiagramGuidelines for Creating Activity Diagrams
4 BPM With Activity Diagrams A number of activities support a business process across several departmentsActivity diagrams model the behavior in a business processSophisticated data flow diagramsAddresses Parallel concurrent activities and complex processes
6 Creating Activity Diagrams 1. Since an activity diagram can be used to model any kind of process, you shouldset the context or scope of the activity being modeled. Once you have determinedthe scope, you should give the diagram an appropriate title.2. You must identify the activities, control flows, and object flows that occurbetween the activities.3. You should identify any decisions that are part of the process being modeled.4. You should attempt to identify any prospects for parallelism in the process.5. You should draw the activity diagram.
8 Key IdeasA use case illustrates the activities that are performed by users of a system.Use cases are logical models -- they describe the activities of a system without specifying how the activities are implemented.
9 What are Use-Case Descriptions? Describe basic functions of the systemWhat the user can doHow the system respondsUse cases are building blocks for continued design activities.
10 How Are Use-Cases Created? Two steps:Write text-based case descriptionsTranslate descriptions into diagramsDescribes one and only one function, but may have multiple paths.Developed working with users for content.
11 Types of Use-Cases Overview versus detail Essential versus real ■ The use case represents an important business process.■ The use case supports revenue generation or cost reduction.■ Technology needed to support the use case is new or risky and therefore will require considerable research.Essential versus real
12 Elements of a Use-Case Description Use Case Name: ID: Importance Level:Primary Actor: Use Case Type:Stakeholders and Interests:Brief Description:Trigger:Relationships: (Association, Include, Extend, Generalization)Normal Flow of Events:Subflows:Alternate/Exceptional Flows:
13 Guidelines for Creating Use-Case Descriptions Write each step in “SVDPI” formClarify initiator and receivers of actionWrite from independent observer perspectiveWrite at same level of abstractionEnsure a sensible set of stepsApply KISS principle liberallyWrite repeating instructions after the set of steps to be repeated.
19 CREATING USE-CASE DESCRIPTIONS AND USE-CASE DIAGRAMS
20 Major Steps in Writing Use-Cases Case DiagramsIdentify the major use-casesExpand the major use-caseConfirm the major use-casesCreate the use-case diagramAs can be seen by comparing this list to figure 6-7, it is a very high levelsummary. Teachers of this material might want to spend significant time reviewingwhat happens in each of these steps.
21 Identifying the Major Use-Cases Identify the system’s boundariesList the primary actorsList the goals of each primary actorIdentify and write the major use-casesCarefully review use-cases
23 Expand the Major Use-Cases Choose one major use-case to expandFill in details on the use-case templateFill in the steps of the normal flow of eventsNormalize the size of each stepDescribe alternate or exceptional flowsSimplify and organize as necessary
24 Confirm the Major Use Cases Review the current setConsider semantics and syntaxHelpful to involve the usersIterate the entire set of steps until all use cases are defined
25 Create the Use-Case Diagram Start with system boundaryPlace elements in order to be easy to readPlace actors on the diagramConclude by connecting actors to use cases by lines
26 Selecting the Appropriate Techniques Interviews JAD Questionnaires Document ObservationAnalysisType of As-Is As-Is As-Is As-Is As-IsInformation Improve Improve. Improve.To-Be To-BeDepth of High High Medium Low LowInformationBreadth of Low Medium High High LowIntegration Low High Low Low Lowof Info.User Medium High Low Low LowInvolvementCost Medium Low Low Low Low-Medium Medium
27 Refining Project Size with Case Points Create essential use cases and use case diagramDetermine Unadjusted Actor Weighting TableObtain Unadjusted Use Case Weight TotalCompute value of Unadjusted Use Case Points
28 Expanding the DomainAdditional resources regarding use-cases and many other object-oriented development topics can be found at:
29 SummaryUse-case descriptions are the basis for further analysis and design. They are created based on 7 guidelines and 13 steps.Use-case diagrams present a graphical overview of the main functionality of a system.