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Events and Use Cases . Use case Activity the system carries out Entry point into the modeling process Elementary business processes (EBPs) Basic unit of analysis Initiated by event occurring at specific time and place Discrete system response that adds business value. Figure 5-1
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Events and Use Cases • Use case • Activity the system carries out • Entry point into the modeling process • Elementary business processes (EBPs) • Basic unit of analysis • Initiated by event occurring at specific time and place • Discrete system response that adds business value Object-Oriented Analysis and Design with the Unified Process
Figure 5-1 Identifying Use Cases by Focusing on Users and their Goals Object-Oriented Analysis and Design with the Unified Process
Event Decomposition • Event decomposition • Develops use cases based on system response to events • Perceives system as black box interfacing with external environment • Keeps focus on EBPs and business requirements • Result of the decomposition: • List of use cases triggered by business events • Use cases at the right level of analysis Object-Oriented Analysis and Design with the Unified Process
Types of Events • External Events • Occur outside the system • Usually caused by external agent • Temporal Events • Occurs when system reaches a point (deadline) in time • State Events • Asynchronous events responding to system trigger Object-Oriented Analysis and Design with the Unified Process
Figure 5-3 External Event Checklist Object-Oriented Analysis and Design with the Unified Process
Figure 5-4 Temporal Event Checklist Object-Oriented Analysis and Design with the Unified Process
Figure 5-7 Events Deferred until Later Iterations Object-Oriented Analysis and Design with the Unified Process
Figure 5-10 Information about each Event and the Resulting Use Case in an Event Table Object-Oriented Analysis and Design with the Unified Process
Problem Domain Classes • Problem domain • Set of work-related “things” in system component • Things have data representation within system • Examples: products, orders, invoices, customers • OO approach to things in problem domain • Objects that interact in the system • Identify and understand things in problem domain • Key initial steps in defining requirements Object-Oriented Analysis and Design with the Unified Process
Figure 5-12 Types of Things Object-Oriented Analysis and Design with the Unified Process
Developing an Initial List of Things • List nounsusers mention when discussing system • Event table as source of potential things • Use cases, external agents, triggers, response • Select nouns with questions concerning relevance • Further research may be needed Object-Oriented Analysis and Design with the Unified Process
Figure 5-14 Associations Naturally Occur between Things Object-Oriented Analysis and Design with the Unified Process
Attributes of Things • Specific details of things are called attributes • Attributes – sound familiar? • Analyst should identify attributes of things • Identifier (key): attribute uniquely identifying thing • Examples: Social Security #, vehicle ID #, or product ID # • Compound attribute is a set of related attributes • Example: multiple names for the same customer Object-Oriented Analysis and Design with the Unified Process
Domain Model Class Diagram Notation • Class diagram key • General class symbol: rectangle with three sections • Sections convey name, attributes, and behaviors • Methods (behaviors) not shown in domain model class diagram • Lines connecting rectangles show associations • Multiplicity reflected above connecting lines • Domain class objects reflect business concern, policies, and constraints Object-Oriented Analysis and Design with the Unified Process
Figure 5-21 An Expanded Domain Model Class Diagram Showing Attributes Object-Oriented Analysis and Design with the Unified Process
Figure 5-25 A Generalization/Specialization Hierarchy Notation for Motor Vehicles Object-Oriented Analysis and Design with the Unified Process