2003 SJSU -- CmpE L7-S1 UC Diagrams Advanced Object-Oriented Analysis & Design Dr. M.E. Fayad, Professor Computer Engineering Department, Room #283I College of Engineering San José State University One Washington Square San José, CA 95192-0180 http://www.engr.sjsu.edu/~fayad
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
2003 SJSU -- CmpE L7-S1 UC Diagrams
Advanced Object-Oriented Analysis & Design
Dr. M.E. Fayad, Professor
Computer Engineering Department, Room #283I
College of Engineering
San José State University
One Washington Square
San José, CA 95192-0180
http://www.engr.sjsu.edu/~fayad
2003 SJSU – CmpE --- M.E. Fayad L7-S2 UC Diagrams
2
Lesson 7:Use Case Diagrams
2003 SJSU – CmpE --- M.E. Fayad L7-S3 UC Diagrams
Lesson Objectives
Objectives
3
Overview of Previous Lecture Use Case Models and Diagrams Notation
Discuss the following:
– What is use case modeling?
– Use Case Modeling -- Core concepts
– Use Case Diagram tour
– When to model use cases
– Use Case Modeling tips
– Use Case Templates
– Examples: Library & University Registration
2003 SJSU – CmpE --- M.E. Fayad L7-S4 UC Diagrams
Use Case Modeling: Core ElementsUse Case Modeling: Core Elements
4
Construct Description Syntax
use case A sequence of actions, including variants, that a system (or other entity) can perform, interacting with actors of the system.
actor A coherent set of roles that users of use cases play when interacting with these use cases.
system boundary
Represents the boundary between the physical system and the actors who interact with the physical system.
UseCaseNam e
ActorNam e
2003 SJSU – CmpE --- M.E. Fayad L7-S5 UC Diagrams
Use Case Modeling: Core Relationships Use Case Modeling: Core Relationships (1)Construct Description Syntax
association The participation of an actor in a usecase. i.e., instance of an actor andinstances of a use case communicatewith each other.
extend A relationship from an extension usecase to a base use case, specifyinghow the behavior for the extensionuse case can be inserted into thebehavior defined for the base usecase.
generalization A taxonomic relationship between amore general use case and a morespecific use case.
5
<<extend>>
2003 SJSU – CmpE --- M.E. Fayad L7-S6 UC Diagrams
Use Case Modeling: Core Relationships Use Case Modeling: Core Relationships (2)
6
Construct Description Syntax
include An relationship from a base use caseto an inclusion use case, specifyinghow the behavior for the inclusion usecase is inserted into the behaviordefined for the base use case.
<<include>>
Multiplicities are missing!
2003 SJSU – CmpE --- M.E. Fayad L7-S7 UC Diagrams
Shows use cases, actor and their relationships
Use case internals can be specified by text and/or interaction diagrams
Kinds–use case diagram–use case description
7
Use Case Diagram Tour
2003 SJSU – CmpE --- M.E. Fayad L7-S8 UC Diagrams
Model user requirements with use cases. Model test scenarios with use cases. If you are using a use-case driven method
– start with use cases and derive your structural and behavioral models from it.
If you are not using a use-case driven method– make sure that your use cases are consistent
with your structural and behavioral models
8
When to model use cases
2003 SJSU – CmpE --- M.E. Fayad L7-S9 UC Diagrams
Make sure that each use case describes a significant chunk of system usage that is understandable by both domain experts and programmers
When defining use cases in text, use nouns and verbs accurately and consistently to help derive objects and messages for interaction diagrams
Factor out common usages that are required by multiple use cases– If the usage is required use <<include>>– If the base use case is complete and the usage may be
optional, consider use <<extend>> A use case diagram should
– contain only use cases at the same level of abstraction– include only actors who are required
Large numbers of use cases should be organized into packages 9
use case model: a view of a system that emphasizes the behavior as it appears to outside users. A use case model partitions system functionality into transactions (‘use cases’) that are meaningful to users (‘actors’).
We must now identify the users of the system and the tasks they must undertake with the system. The details of the use case should be documented, using a Use Case Template.
There are many different use case templates Show a few!!
Use Case Template & Example: Change Flight Use Case #: 1.0 Use Case Name: Change flight Actors: traveler, client account db, airline reservation system Preconditions:
Traveler has logged on to the system and selected ‘change flight itinerary’ option
Basic course System retrieves traveler’s account and flight itinerary from client account database System asks traveler to select itinerary segment she wants to change; traveler selects itinerary segment. System asks traveler for new departure and destination information; traveler provides information. If flights are available then … System displays transaction summary.
Alternative courses If no flights are available then …
Use Case TemplatePACKAGE: _________________ [Description (an over view of the package)].USE CASES: [A package will have one or more Use Cases].Use Case No.: [1.1]Use Case Title: [A descriptive title]
[Ex. adding a new patient, or adding a new role].Actors: _______, _______, _______, _______.
[Any users of the Use Case, ex. human, machine, other systems or subsystems].Corresponding Roles: _______, _______, _______, _______.
[There is a different role per actor in every Use Case].Classes: _______, _______, _______, _______.
[List all the classes within the Use Case Description].Corresponding Attributes and Behaviors: Enduring Business Themes (EBT): _______, _______, _______Business Objects (BO): _______, _______, _______, _______.Industrial Objects (IO): _______, _______, _______, _______.
[This represents a clear classification of all the classes within the use case description].
Description of the Use Case:[Describes the data flow and the logic flow of the Use Case].
You have been contracted to develop a computer system for a university library. The library currently uses a 1960s program, written in an obsolete language, for some simple bookkeeping tasks, and a card index, for user browsing. You are asked to build an interactive system which handles both of these aspects online.*
*Example from: “Using UML”, by: Pooley and Stevens
The usual course through the system when actor is using the system is called the basic course. Other courses would be modeled as extending Use Cases.
An example of a basic course would be: – Borrow copy of book A BookBorrower presents a book. The
system checks that the potential borrower is a member of the library, and that s/he does not already have the maximum permitted number of books on loan. This maximum is six unless the member is a staff member, in which case it is 12. If both checks succeed, the system records that this library member has this copy of the book on loan.
**Example from: “Using UML”, by: Pooley and Stevens 42
Books and Journals: The library contains books and journals. It may have several copies of a given book. Some of the books are for short term loans only. All other books may be borrowed by any library member for three weeks. Only members of staff may borrow journals. Members of the library can normally borrow up to six items at a time, but members of staff may borrow up to 12 items at one time. New books and journals arrive regularly, and are sometimes disposed of. The current year’s journals are sent away to be bound into volumes at the end of each year.*
*Example from: “Using UML”, by: Pooley and Stevens
Borrowing: It is essential that the system keep track of when books and journals are borrowed and returned, since the current system already does that. The new system should produce reminders when a book is overdue. There may in future be a requirement for users to be able to extend the loan of a book if it is not reserved.
Browsing: The system should allow users to search for a book on a particular topic, by a particular author, etc., to check whether a copy of the book is available for loan, and if not, to reserve the book. Anyone can browse in the library.*
*Example from: “Using UML”, by: Pooley and Stevens
The ESU University wants to computerize their registration system– The Registrar sets up the curriculum for a semester
• One course may have multiple course offerings– Students select 4 primary courses and 2 alternate courses– Once a student registers for a semester, the billing system is
notified so the student may be billed for the semester– Students may use the system to add/drop courses for a period of
time after registration– Professors use the system to receive their course offering rosters– Users of the registration system are assigned passwords which
This use case begins when the Registrar logs onto the Registration System and enters his/her password. The system verifies that the password is valid (E-1) and prompts the Registrar to select the current semester or a future semester (E-2). The Registrar enters the desired semester. The system prompts the professor to select the desired activity: ADD, DELETE, REVIEW, or QUIT.
If the activity selected is ADD, the S-1: Add a Course subflow is performed.
If the activity selected is DELETE, the S-2: Delete a Course subflow is performed.
If the activity selected is REVIEW, the S-3: Review Curriculum subflow is performed.
If the activity selected is QUIT, the use case ends. 50
Use Case No.: 1.1.1 Use Case Title: Find Candidate Actors: Registrar Roles: Data Entry Clerk (Registrar), Classes: IDSession, PersonProfile, PersonIdentifier,
PersonTraits , CandidateListGenerator, DataManager Enduring Business Themes: (EBT): identity, security, Business Objects: IDSession, IDManager, DataManager,
Description of the Use Case: 1. The Registrar enters the information about a person into the
System. 2. IDSession clears the request with Security. 3. The System tells the Person-Identifier to search for candidates. 4. The Person-Identifier gives the request to its DataManager 5. The DataManager determines a list of candidates, using its
CandidateListGenerator and its set of PersonProfiles and returns it to the System.
6. The Registrar chooses the candidate from the list that represents the person.
Use Case No.: 1.2.1 Use Case Title: Register New ID Actors: Registrar Roles: Data Entry Clerk (Registrar), Classes: IDSession, IDManager, PersonProfile, PersonTraits,
CandidateList, PersonIdentifier Enduring Business Themes (EBT): identity, security Business Objects (BO): IDSession, IDManager, PersonIdentifier
Description of the Use Case: 1. The Registrar enters the information about a person into the IDSession. 2. The IDSession has security clear the request. 3. The IDSession has the PersonIdentifier search for candidates. 4. The Person-Identifier determines that no candidates fit the criteria. 5. The Person-Identifier gives this information to the system. 6. The informs the Registrar that no candidates exist. 7. System asks the Registrar if the person should be added as new. 8. Registrar tells System to add new person. 9. System sends traits to ID-Manager. 10. ID-Manager creates a new profile.
Exceptional Flow of Events 01: If any of the identifying information entered by the Registrar is incomplete or invalid the system displays corresponding error message(s). The system will not validate the New Person until all identifying information is made available.
Exceptional Flow of Events 02: In case the system determines that one or more of the identifying information for a person matches one or more person(s) already in the system the Registrar is displayed with a screen listing all the person(s) meeting the search criteria. The Registrar is then given the opportunity to either create the person in the system with a new ID or pick one from the selection list.
2. The Person Identification system determines the validity of the Person ID.
3. The Get Profile System returns the profile the specified Person ID.
Exceptional Flow of Events 01: If the Person ID is invalid an error message is displayed. The nurse then can decide either to search the system with person identification information or redirect the person to a Registrar.
association The participation of an actor in a use case. i.e., instance of an actor and instances of a use case communicate with each other.
inheritance It is a AKO or is-a relationshipThis relationship
includes extend and generalization. A taxonomic relationship between a more general use case and a more specific use case and relationship from an extension use case to a base use case, specifying how the behavior for the extension use case can be inserted into the behavior defined for the base use case.
Task 1: Problem Statement for team projects are needed (see sample problems on OOPSLA – DesignFest). This is due on the third week of the semester.
Task 2: Identify the team members of your team. Select a team name and e-mail me, the team name, team’s members’ names, their e-mails, phone numbers -- Immediately.
Task 3: Think about extra assignments and writing essays. E-mail me if you like to start right away.
Please note that problem statements must be submitted electronically as MS Word format. 71