Class Notes (838,936)
Canada (511,158)
York University (35,553)
ITEC 3010 (26)
all (20)
Lecture

lecture_7 notes.doc

5 Pages
100 Views
Unlock Document

Department
Information Technology
Course
ITEC 3010
Professor
All Professors
Semester
Winter

Description
Systems Analysis and Design I ITEC3010 – Fall 2010 – Luiz Cysneiros Lecture 7 – Object-Oriented Approach to Requirements – Nov 2 The Unified Modeling Language and the Object Management Group - Object-oriented modeling notation is Unified Modeling Language (UML) - UML was presented to Object Management Group (OMG) as standard modeling technique - Purpose of Object Management Group o Promote theory and practice of object technology for development of distributed systems o Provide common architectural framework for OO Object-Oriented Requirements - Object-oriented system requirements are specified and documented through process of building models - Systems development process starts with identification of events and things - Events are business processes that new system must address - Things are problem domain objects involved in business process Object-Oriented Approach Models - Class diagram – definition of system components - Use case diagrams and use case descriptions – What are user roles and how they use the system - Systems sequence diagrams (SSDs) – define inputs and outputs and sequence of interactions between user and system for a use case - State chart diagrams – describe states of each object - Activity diagrams – describe user activities Overview - The objective of requirements definition is understanding – understanding the users’ needs, the business processes, and the systems to support business processes - Understand and define requirements for a new system using object-oriented analysis models and techniques - Line between object-oriented analysis and object-oriented design is somewhat fuzzy o Iterative approach to development o Models built in analysis are refined during design The Class Diagram - There are two kinds of descriptions of systems o Structural information (components of the system) o Behavioral information (logic performed by components) - Class diagram provides definition of structural components of the system - The other OO diagrams (e.g. use case, sequence, collaboration) focus on activities the system performs - NOTE – with OO Analysis, the class diagrams describes system requirements that can map very closely to the structure (i.e. classes) in the OO computer program that will be eventually created - Hierarchies that structure or rank classes from the more general superclass to the more specialized subclasses (sometimes called inheritance hierarchies) - Generalizations o Group similar types of things like all cars share certain features (e.g. All cars have wheels, engine etc.) - Specializations o Are judgments that categorize different types of things (e.g. Sports car is a special type of car) - A generalization/specialization hierarchy structures things from the general down to the more special o Each class has a more general class above it – a superclass o A class may have a more specialized class below – a subclass - Inheritance: a concept that allows subclasses to share characteristics of their super classes - E.g. a sports car has everything a car has (e.g. 4 wheels and an engine, which it “inherits” from the class car which is above it) - The sports car then specializes o E.g. has a sports option, racing wheels etc. Learning Objectives - Understand the models and processes of defining object-oriented requirements - Develop use case diagrams and activity diagrams - Develop system sequence diagrams - Develop state machine diagrams to model object behaviour - Explain how UML diagrams work together to define functional requirements for the object-oriented approach The System Activities – A Use Case/Scenario View - Use case analysis used to identify and define all business processes that system must support - Use case – an activity a system carried out, usually in response to a user request - Actor o Role played by user o Outside automation boundary Techniques for Identifying Use Cases - Identify user goals o Each goal at the elementary business process (EBP) level is a use case o EBP – task performed by one user in one place and in response to business event that adds measurable business value, and leaves system and data in consistent state - Event decomposition technique (event table) - CRUD analysis technique (create, read/report, update, delete) to ensure coverage
More Less

Related notes for ITEC 3010

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit