I'm doing a use case diagram for taxi booking system. Below is the link to the use case diagram:
http://img260.imageshack.us/usecasediagram.jpg/
I’m not sure if I need to include customer (actor) in the diagram. If I assume that “phone lines” are part of the system, than I think it makes sense to include customer.
I used to approach use case diagrams in a, say holistic way; so every stackholder/party should be included.
And the customer <-> system interaction seems like a system use case - maybe you should enhance your diagramm with some verbs:
A system use case is normally described at the system functionality level (for example, create voucher) and specifies the function or the service that the system provides for the user. A system use case will describe what the actor achieves interacting with the system. For this reason it is recommended that a system use case specification begin with a verb (e.g., create voucher, select payments, exclude payment, cancel voucher). Generally, the actor could be a human user or another system interacting with the system being defined.
Source: Article on Use Case
PS: Use case diagrams are kind of high-level and appear in the start of a software development process. Other, more fine grained artifacts will emerge along the way.
PPS: And in the end, users are often (kind-of) ignored in traditional development models, so i think its never bad to sketch them on at least one diagram ...
I would include them. Your assumption makes sense, and since they do have a direct interaction that causes the system to execute some functionality, I believe that is a legitimate use case that should be modeled lest it be forgotten at some point downstream.
