1. The Unified Modeling Language
(UML)
References: Jacquie Barker,Beginning Java Objects; Martin Fowler,UML Distilled,
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2. UML
Programming is like building a house. An architect creates a design, and a builder uses appropriate tools to carry out the design. The builder does not proceed without a blueprint from the architect.
Software developers also need a blueprint to create complex systems.
The UML is a toolbox of graphical notations used to produce the blueprint -- a graphical depiction of the software design
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3. UML Many Object technologists were influential contributors to UML:
James Rumbaugh : the Object Modeling Technique (OMT)
Grady Booch : the Booch Method (clouds)
Sally Schlaer and Stephen Mellor : state diagrams, recursive design approach
Rebecca Wirfs-Brock : Responsibility driven design
Beck and Cunningham: CRC cards
Bertrand Meyer : Eiffel and ‘programming by contract’
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4. UML Many Object technologists were influential contributors to UML:
Ivar Jacobsen : use cases for formalizing requirements
James Martin and James Odell : books on Information Engineering
Peter Coad and Edward Yourdon: lightweight, prototype-oriented approach to methods
Derek Coleman (HP) : the Fusion method
Erich Gamma, Richard Helm, Ralph Johnson, John Vlissides – “the Gang of Four” : Design Patterns
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5. UML
Experts in object technology argued for years over notations and process.
Software developers could choose from many different methodologies to express their designs; there was no standard means of communication.
UML was the outcome of the “methodology wars”.
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6. UML
Jacobsen, Rumbaugh and Booch - dubbed “The Three Amigos” - joined their competing modeling languages into one to create a standard notation (i.e. common vocabulary) that developers can use to convey their designs.
UML was adopted as the standard for the OMG (Object Management Group) – a consortium that includes over 800 members– in 1997
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7. UML
UML is not a method. It does not outline a procedure for designing software; it is a modeling language that captures the design graphically.
Most methodologies consist of a modeling language and a process
Whatever process you use, you can use UML to record the results of your analysis and design decisions.
Diagrams emerge independent of some process.
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8. UML The main reason to use UML notation is communication.
To discuss design with someone, both need to understand the modeling language, not the process used to come up with the design.
Human language is imprecise
Code is too detailed
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9. UML Class Diagrams Student
In the analysis & design phases, class diagrams are used to organize the attributes and operations of a class.
The simplest class diagram lists only the names of attributes without their types, and lists method names without parameters or types.
Student
Simplicity is good
name
ssn
birthdate
gpa
‘get’ and ‘set’
methods are
implied and
not shown
registerForCourse()
dropCourse()
chooseMajor()
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10. Basic Class Notation A box represents a class
Topmost box is the name of the class
Middle box lists attributes
Bottom box contains operations
Graphical notes about your model are depicted in boxes with folded corners
Class name
<<Class name>>
<<Attribute>>
Attributes
<<Operations>>
In UML an ‘operation’ is a service that you can request from any object of a class; a ‘method’ is a specific implementation of the operation.
Operations
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11. The characters -, #, and + convey visibility
Basic Class Notation
The characters -, #, and + convey visibility
Visibility
+ public_attr
# protected_attr
- private_attr
+ public_opr()
# protected_opr()
- private_opr()
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12. Basic Class Notation Class diagram for the BankAccount class
- balance : double
+ depositFunds(amount:double):void
+ getBalance():double
# setBalance():void
+ withdrawFunds(amount:double):double
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13. Example of a note that conveys meaning
Basic Class Notation
Example of a note that conveys meaning
Bank
+ addAccount()
+ totalHoldings()
+ totalAccounts()
+ deposit()
+ balance()
The bank holds onto a number of
Accounts and provides operations
For manipulating those accounts.
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14. Static attributes are underlined
UML Class Diagrams
Static attributes are underlined
Student
totalStudents
name
ssn
birthdate
gpa
registerForCourse()
dropCourse()
chooseMajor()
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15. Simplified Class Diagram
To avoid getting too detailed during analysis, you can convey only the public interface of a class, without all the details of method arguments and attributes.
Bank
addAccount()
totalHoldings()
totalAccounts()
deposit()
balance()
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16. Stereotypes
You can make a model more descriptive by using stereotypes.
A stereotype is a UML element that allows you to extend the vocabulary of the UML language. It consists of a word or phrase enclosed in << >>.
A stereotype is placed above or to the side of an existing element.
BankAccount
<<accessor>> +getBalance()
+ depositFunds()
+ withdrawFunds()
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17. Stereotypes Stereotypes
To indicate a class is an abstract class, you either use italic font for the class name or add a constraint.
BankAccount
{abstract}
- balance : double
+ depositFunds(amount:double):void
+ getBalance():double
# setBalance():void
+ withdrawFunds(amount:double):double
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