Effective Use Cases

[Jon Tobias Fors]

Hi all !

I'm interested in your opinion on how the support for use cases could be improved in Enterprise Architect.

Specifically, it would be nice to be able to customize the data entry form form used for writing use cases. Remember that use cases are primarily textual specifications!

See for example www.usecases.org, for a highly interesting approach to use cases, spearheaded by Alistair Cockburn.

[mch]

Hi Jon,
we've used EA's scenarios to successfully capture and structure use cases. It took a bit of trial and error to come up with but now the approach works well.

Each use case is described in the notes including triggers, pre- and post-conditions. Each flow is set up as a scenario and numbered following Alistair's approach. Each scenario has a type indicating main flow, alternate flow, exception, subflow or whatever is appropriate for your organisation. The new HTML generator does a nice job of rendering these.

I strongly recommend Alistair's book, Writing Effective Use Cases as an excellent, comprehensive approach for anyone preparing use cases.

Cheers,
Mark

[MattD]

I think Jon makes a good point.

While the interface for adding creating and customising use cases isn't bad in EA, it is a bit clunky to use.

EA only allows the writer to view one main flow/alternate/subflow at a time. Writing a use case requires chopping and changing between the different flows in order to get the text correct and consistent. In order to do this in EA the writer has to save what they are doing, click on the flow they want to view, save any changes there, and then click on the original flow to bring it up again.

Given that use cases are textual, what would make adding the use case text a lot simpler is an easy way to view one or more flows at a time, and a spell checker that checks just that use case that is initiated from the same pop up box that is being worked on.

If this sounds like I would like a word processor in the use case pop up box, this is true. While this may be unrealistic, going some way to having some of the attributes of this would make adding a use case a lot less time consuming.

Matt

[sbaishya]

I too am keen on Alistair's work on use cases. My current thinking is to simply paste the text version of Alistair's use case template into the "Note" field of EA's use case dialog. I'm inclined to think that lots of fields and drop-down lists can confuse the process.

As MattD says, use cases are textual, and I think it may be better to handle them as such, ie: a single entity rather than split into their constituent parts. This could be done quite elegantly if EA allowed one to specify a text file as a template for the Note field of the use case dialog.

[MattD]

My wish list, in order of importance, for making use cases in EA easier to add is the ability to:

-View the main flow at the same time as adding alternate flows.
-View previous alternate flows (not just headings) at the same time as adding alternate flows.
-Specify the fields of the 'header details' of a use case, e.g. preconditions, triggers, minimal guarantees etc. I know that this can be done to a degree at the moment.
-Spell check a specific use case
-Link a specific requirement to a specific use case step.
-Specify auto numbering style for use case steps and alternate flows (e.g. 1, 1.1, 1.2 or 1a, 1b, 1c and 1a1, 1a2, 1a3 etc)

I don't mind whether this is achieved by specifying a text file as a template or (a great idea) or making the changes to the EA interface.

I feel that treating each component of a use case as a separate entity is making things unnecessarily complicated. No code is generated directly from the use case descriptions, so surely the use case components are just labels that we attach for the benefit of formatting?

Matt

[Darren Lock]

This is an interesting one for sure.

I agree with the comments of this thread in that it is difficult to format the Use Case for documented output. I think I may have previously requested that some of the edit boxes support rtf or html so that the content could be formated in subsequent output. It is also time consuming to enter a Use Case via a series of dialogs (although this appears to be the approach taken by most modelling/CASE tools).

Currently, I am using the ActiveX interface to retrieve the Use Case components and format them into a Word document. Therefore, I would prefer the Use Case components to remain seperate. Note that I have modelled the Use Case Trigger by adding a new constraint called Trigger.

Maybe what is required is some kind of data entry window that is based on the the underlying Use Case XML schema/components but allows the user to configure which components are displayed via some kind of template (XSL ?)

Darren