Lecture 4

Question 1

how do we represent class and name in uml? and abstract class?

Answer 1

rectangle, words and name start with capital, name can also be pathname package::class. abstract - name is in italics

Question 2

what are the components of a class rectangle?

Answer 2

0 - name, 1 - attributes, 2 - operations (functions), 3+ - other features

Question 3

how are attributes represented in UML?

Answer 3

name, can have type, visibility, default value, derived value, multiplicity

Question 4

explain visibility and symbols (also multiplicity, derived and default value)

Answer 4

+ - public, - - private, # - protected, = - default, / - derived, [] - multiplicity. eg -/age : integer, -date : Date = today, middleName[0…2] (attribute can have 0 - 2 values)

Question 5

what is the correct uml way to write operation?

Answer 5

have a name, optional: visibility, parameter names and types, return type

Question 6

what is the difference between instance and class scope?

Answer 6

class-scope attributes - same for all instances of class (interest rate)
instance-scope attributes - different instances of the class can have different values
default - instance

Question 7

explain what an association is

Answer 7

-name, roles the participating objects play. eg word that goes on line between 2 classes

Question 8

explain relationships of different degrees

Answer 8

reflexive - involves instances of the same class
binary - degree 2, ternary - degree 3, n-ary - more than 3

Question 9

multiplicities of higher degree relationships

Answer 9

eg relationship between country, company and product. on product have 0..10, each company can only 10 products to same country

Question 10

how do we represent constraints?

Answer 10

eg person if related to itself (person marries person), a box that says (p1 and p2 can marry if both over 18) and connected to relationship line with dotted line

Question 11

what is an association class?

Answer 11

a class that comes off of a relationship line (if the association (relationship) need info about itself or behaviour)

Question 12

how do we show an object and link diagram?

Answer 12

box(e1 : employee) connected with line to box(p1:permit) and box(p2:permit)