CS2103T: Lecture 4

UML Diagrams

Multiplicities

0..1 = if its there then it is there, else it is not.

Navigability

In the class diagram, 

[] ------- []

does not show who knows who

thus we use arrows

[a]------>[b]

class a{

b someObj = new b();

}

class a knows about b but 

b does not know about a

[A] ---

  |       |

  |       | longest

[B]  <-

A is maintaining B

longest is the role for B

The object structures can change at runtime,

the association cannot change out of what is specified in the class diagram

[:foo] -> instance object

[foo] -> class object

Inheritance

Inheritance can be represented by a triangle.

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