Use Case scenarios

[jamesj]

The Use Case standard for scenarios that I have used in the past has a "User Action" and "System Response" column rather than just one.

You put something like "User clicks OK" in the UA column and say "Screen details are validated" in the SR column, and so it goes through each step of the scenario.

I have been trialling EA for about an hour now so forgive me if there is a way to do this.

Can this be done, or is it just how EA is designed?  

[PhilR]

Hi James,

EA does not really support this style of use case scenario and I can't really think of a way to achieve it other than linking the use case to an external wordprocessor file that held the use case scenario.  See Use case Properties|Files tab to do this.

Even if EA does not suit your preferred use case format I would encourage you to evaluate it further as it is an awesome product.

Phil

[jamesj]

Thanks for the confirmation.  It's nice to know I was on the right track.

As you suggested, I plan to use an external file for the scenario notes.

[Eric_Carroll]

This thread is old, but I wanted to add one comment.

I understand a UC scenario to be a data fill of the use case, in other words, a specific instance of the use case with given data.

However, this is not how I use EA scenarios. I use EA "scenarios" to encode Use Case "Alternative Paths", i.e. exceptions or alternatives to the basic path. This keeps my basic path nice and clean and tight. I then encode the alternative paths as scenarios. This looks good on the documentation, too, and reads well.

There is no real mechanism in EA, except perhaps "Test Cases" to capture the meaning of scenarios as data fill, i.e. the two column view.

I might drop Geoff a note to see what he thinks about clarifying the language, as I was initially quite confused about what EA scenarios were intended for.

How do other people use EA scenarios?

[molla]

I use them like you suggested, namely my scenarios depict the main and alternative flows for the use case. I then go ahead and define sequence diagrams for each one of the scenarios, and then complement it with test cases for each of the scenarios. During this process, I do not neglect to provide the links to the actual requirement objects as well.

[MichaelRuschena]

I use scenarios for basic and alternate flows as well. I'm not sure what a "data fill" is, but could it be captured by defining another type of scenario, and just putting the text in?

I do not neglect to provide the links to the actual requirement objects as well.

Molla, I'm very interested in the fact that you do this. We've been thinking about trying this, but it seems like a very manual process. I wonder if you could say a few words about the benefits you get from this, how detailed you make the requirements, and what (if any) use you make of the explicit tracability.

To actually capture this, I'm assuming you're using the requirements icon in the custom diagram, possibly with aggregation or association links between them as appropriate. Is this way off target?


thanks

[jaimeglz]

Hi all,

I don't think that the two column approach ("User Action" and "System Response") is a good practice, because use cases can represent manual tasks that have no interaction with a system. For example, in the Human Development Indexes project we are carrying out for the Mazatlan Villa de Flores municipality, we have to describe a "fill family questionnaire" use case: questioner asks family head for family home data detailed in questionnaire (form) page 1; questioner writes family home data on family data on form, page 1...

I agree with Eric et al. that one of the most fundamental aspects of use cases is to obtain the basic path and alternative paths.

I don't write the detailed event list of the basic path or alternative paths in the scenario section of the use case dialog in EA (though I do write a very brief description of these, or at least something that can remind me and/or other modeler or programmer that some alternative path has to be considered as well). But I do obtain a detailed event list from the sequence diagram(s) that describe the use cases' path(s).

However, I do not mean to deny that what is being called "data fill" can be valuable. In order to obtain with EA something very similar to what James is looking for, I would suggest the following:

1. Create a sequence diagram that describes your scenario (prefferably directly under your use case, if this does not interfere with the way you order your project packages).
2. Generate the RTF documentation of the package that contains your sequence diagram (right click on the package -> Documentation -> Rich Text...   ).

The resulting RTF will contain a column formatted event list of your sequence with "Message", "From Object", "To Object" and "Notes". Example:
(message:) double click, (from object:) user, (to object:) ico_system;
display(w_login)... etc

You can actually change the order of the event list columns in the RTF doc: go to the resources tab of your Project Workspace -> expand Templates, right click on RTF Templates, create an RTF template, and modify the sequence of cells in both Sequence Heading and Sequence Line items. When generating your RTF doc, use the "Style" drop-down list to specify the RTF template you have just saved.

I hope this can be of some help.

Jaime Gonzalez

[molla]

Molla, I'm very interested in the fact that you do this. We've been thinking about trying this, but it seems like a very manual process. I wonder if you could say a few words about the benefits you get from this, how detailed you make the requirements, and what (if any) use you make of the explicit tracability.

To actually capture this, I'm assuming you're using the requirements icon in the custom diagram, possibly with aggregation or association links between them as appropriate. Is this way off target?

I define my basic use cases in a kind of "Use Case Model Survey" a la Rational, then go on to define them individually by means of sequence diagrams. I use a separate use case diagram for any substantial use case that covers a couple of requirements. Using this scheme, my use case diagram shows the realization link between the use case and the requirement(s) and any aggregation links between different requirements covered by the use case in its various scenarios.

This seems to work and also results in nice documentation.

Levent Mollamustafaoglu