The Use-Case Model
Last updated: May 10, 2006
Objectives: After completing this module, you'll be able to
Describe a use-case model, its components, and its importance.
Explain what is used to create use-case diagrams in Rose.
Use the Rose tool to create a use-case diagram to clearly illustrate what the system will do.
Use the Rose tool to create an activity diagram to visually illustrate a use case's flow of events.
The Use-Case Model:
Is created in the Use-Case View of Rose.
Is a model of the system's intended functions and its environment.
Serves as a contract between customer and developer.
Is essential to analysis and design and test activities.
Can include use-case diagrams, use-case flow of events, supplemental information, and activity diagrams.
Is created using artifacts developed by the software architect and system analysts in concert with the customer. An artifact is information produced, modified, or used by a process. It defines and area of responsibility and is subject to version control. An artifact can be a model, a model element, or documentation.
Use-Case Diagrams
Can be modeled in a number of ways:
All actors and use cases (global view).
All the use cases for a selected actor.
A single use case and all its relationships.
All the uses cases used in an iteration.
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Are typically created from numerous sources that may include the following:
Glossary
Stakeholders request
Vision document
Use-case modeling guidelines
Business use-case model
Business object model
Supplemental specifications
Relationships:
The navigation direction represents who is initiating the communication.
The end with the arrow indicates who or what is receiving the communication.
Flow of Events:
In Rose, you include each use case's flow of events in the Use-Case View.
A flow of events is included under its use-case package in Rose and can be accessed directly from Rose once it's attached.
Artifacts:
Can be both input and output artifacts depending on the activity.
Are important to the use-case model and should be attached to the model in Rose. These documents may include the glossary, vision, stakeholder requests, business use-case model, and so on.
Can be accessed directly from Rose once they're attached.
Activity Diagrams:
Activity diagrams can also be used in business modeling and to model the workings of an operation, an object, or anything that involves modeling the sequential steps in a computational process.
Activity diagrams represent the dynamics of the system.
Activity diagrams are not required. Some prefer its textual counterpart, the flow of events. It's up to you whether you create them to illustrate the workflow of a use case.
Transitions can be labeled with events, guard conditions, or actions using the transition's Specification window in Rose.
Swimlanes:
Each swimlane should represent a responsibility for part of the overall workflow, carried by a part of the organization. A swimlane may eventually be implemented by an organization unit or a set of classes in the business object model.
The relative ordering of swimlanes has no semantic significance. Each activity is assigned to one swimlane and transitions may cross lanes.
Reports:
Show Usage: The Show Usage report lists all the locations where the selected item is used as a supplier in a relationship.
Many items can be suppliers in relationships.
Classes, actors, and use cases can be suppliers for associations.
An operation can be a supplier for a message.
Activities, synchronizations, and states can be suppliers for state transitions.
This report can be used with all Rose diagrams, including use-case and activities diagrams.

Create a Use-Case Diagram:
Add the Use-Case Diagrams to the Browser:
Open Lab4_1.mdl
Expand Use Case View ¡Ð¡Ö Expand Use-Case Model
look at the actors under Actors
look at the use cases under Use Cases
Create Realtor View for actor Realtor
Create Maintain Personal Planner View for use case Maintain Personal Planner.
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Add the Actors and Use Cases to Diagram:
Double-click Realtor View
Referencing the Global View of Actors and Use Cases, determine the use cases associated with the Realtor actor.
Drag the Realtor actor and its use cases from the browser into the diagram window.
Notice that the association relationships are also added automatically.
Similarly, add the actors and use cases for Maintain Personal Planner View.
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Add Use-Case Flow of Events:
Right-click Apply for Loan ¡Ð¡Ö Select a New File
Select ApplyForLoan.txt
You can now double-click the file to open it from Rose.
Similarly, add MaintainPersonal Planner.txt for Maintain Personal Planner; add SearchForHome.txt for Search For A Home.
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Add Project Artifact:
Add the Home Realty System's Problem Statement (ProblemStatement.txt) to the Use-Case Model.
Add text to the documentation window to describe one of your use-case diagrams.
Change the line and/or fill color of a use case.
Create an Activity Diagram:
Add Activity Diagram to the Browser
Right-click Maintain Personal Planner use case (NOT the package) ¡Ð¡Ö New ¡Ð¡Ö Activity Diagram
Name the diagram: Basic Flow ¡Ð¡Ö click outside the name box
Open Basic Flow
Add Activities, start and End States, Transitions, Decisions, and Guard Conditions
Referencing the following Activity Diagram, add the activities to the diagram.
Add the start state and end state(s) to the diagram.
Add the transitions, decisions, and guard conditions
For decisions: Add the decision icon ¡Ð¡Ö Add the transitions
For guard condition text: Open the trasition's Specification Window ¡Ð¡Ö¢ì
To check your competed use-case model : Open Lab4_2.mdl
Run the Show Usage report on any element in a use-case or activity diagram:
Open the diagram ¡Ð¡Ö Select a model element ¡Ð¡Ö Report ¡Ð¡Ö Show Usage