Release date: Tuesday, 26.04.11 - Due date: Sunday, 01.05.11, 23:59

Explain in your own words, in one or two sentences:

1. what does «include», «extends», and generalization between use cases mean.
2. what is the difference between «include» and «extend».
3. what is the difference between «extend» and generalization.

Your colleague collected three scenarios about reserving hotel rooms. She already rearranged them a bit, so that they are already very similar. Abstract (the flow of events of) a Use Case from these scenarios:

Mr. Smith (Click to expand)

Ms. Marple (Click to expand)

Johnny (Click to expand)

Use Case: Reserve Room

1. The customer selects to reserve a room.
2. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
3. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
4. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
5. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
6. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
7. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
8. The system displays the reservation confirmation number and check-in instructions.
9. The use case terminates.

a) Represent the use case of the previous task in form of a sequence diagram. This sequence diagram should show only two objects: The customer and the system.

b) Now we assume that the database is not part of the system that we are specifying but an external system. Change the Sequence diagram accordingly. What would you change in the corresponding use case diagram?

For this task, download and open this astah* file from the SVN.

Study the use case diagram. Afterwards, make sure that it covers the following scenario as well:

Inattentive Heinz charges his card with e-money (Click to expand)

Tip: There are reasons to use each of the possible relationships between use cases.