1. Components and semantics
Computer Science at Karlstad University welcomes the Mälardalen Real-time Research Center, Västerås 1

2. Basic interface model, UML 1.4
Interface with contract
Client component
Supplier component
<<requires>>
<<implements>>
Specify client and supplier interfaces together 2

3. Revised interface model, UML 2.0
Required interface
Offered interface
Client component
Supplier component
<<requires>>
<<offers>>
Specify client and supplier interfaces separately 3

4. Version and purchase management
Client component
Supplier component
<<requires>>
<<offers>>
Client component
Supplier component
<<requires>>
<<offers>>
Client component
Supplier component
<<requires>>
<<offers>>
One to one check between client and supplier = n2 checks 4

5. Interface model needed?
Interface specified by system architect
Interface offered by supplier module
Interface required by client module
Client component
Supplier component
<<requires>>
<<offers>>
Evaluate client and supplier interfaces relative to systems requirements 5

6. Version and purchase management
Client component
Supplier component
<<requires>>
<<offers>>
Client component
Supplier component
<<requires>>
<<offers>>
Client component
Supplier component
<<requires>>
<<offers>>
Each client and supplier checked separately against the system requirements = 2n checks 6

7. Relating interfaces to each other
Inheritance
Version control
Component purchase
Base class
Version A
Client component
time
Derived class
Version B
Supplier component
Works as long as the lower interface contracts define subtypes of (are equal to or ”weaker” than) the upper ones 7