i am confused in drawing a sequence diagram of a use case which includes multiple use cases, should i draw separate sequence diagram for every (included) use case or a single sequence diagram for those use cases?
You ran into a common issue with <<include>> or <<extend>>. If any of both is used, the UC must describe the point where that actually happens. And of course you would not need to expand that part. Instead you refer to the description of I/E UCs. This can be done with diagram gates or by re-using activities.
Related
The above use case diagram is to detect fall
So basically, I was trying to use the 'Alarming', 'send SMS' and 'stop SMS' use case as an extension from the base case 'detection of fall' but they also have include relationship as shown in the diagram. Therefore, I tried to do it as shown in the diagram above
Any comments, please? Is it correct?
If you feel the obligation to indicate if conditions in a use-case diagram, it should probably not be a use-case diagram anymore. Try to represent this as an activity diagram, and simplify your use case to something as simple as “Alert for situations of distress”.
I have seen switch-case recommendations for activity diagram, however I can not find an example for sequence diagram. Do we have to use break keyword while drawing or just drawing conditions only?
I use the alternative block with more than one condition in them, see the pic above
I am not sure about the correctness of this but I use this way to use the switch case in the sequence diagram and it is posted at the link below:
http://www.tracemodeler.com/articles/a_quick_introduction_to_uml_sequence_diagrams/
I’m trying to prepare UML model for my project. It’s quite complex however I focus on one of use-case. In short term, use case name is “Edit patient results” and actor “Doctor” uses it. In fact, entering results triggers always the set of following actions:
List item
Normal Ranges calculation
Related Expression calculation
Interpretation merging
Assuming that I have my use-case diagram prepared as follows:
My questions are:
How shall I draw actions that are triggered automatically? As extended use-cases like this?
How shall I draw “Edit patient results” use-case realization? Each edit operation involves several software components interactions, shall I use collaboration diagrams? (how to join my main use-case with them), maybe something else?
How to draw sequence diagrams to show actions sequence and parameters passed? How to join these diagrams with my use-case.
What is the best way to show use-case realization
I'm using Enterprice Architect.
Thank You !!!
No. These are just activities which are part of scenarios inside the use case. Trying to make the use cases is functional analysis the wrong way. A use case synthesizes a number of steps under a common goal/added value.
A use case realization is a collaboration (bubble with dashed line border; along with the UC in the toolbox). The collaboration contains diagrams which show how the single classes communicate/collaborate to realize (parts of) the use case. Use a Realization from Collaboration to Use Case.
Put the SDs inside the collaboration and group/name them reasonably.
see above
As to your comments:
Edited 2.
I never found a good use for Collaboration Use and I've done a lot of successful UC modeling. So you can probably live without it as well.
Put Actions inside an Activity representing a scenario and connect them as desired. You might look into BPMN as well.
I understand the appropriate use of extend and include , however all the examples I could find draw single large use case diagram with extend or include within the system boundary of that single use case diagram.
Our current project has a base use case diagram with different specialisations from that base use case diagram. Each diagram is on a different page in the document and due to their combined size, including all of them into a single diagram is not a good idea. I would like to know if there is a standard or conventional way of communicating this inheritance tree of separate use case diagrams? If there is not, what would you recommend is the best way to go forward with this dilemma?
Uses Cases inheritance
Does this image extracted from UML speficitaion helps you ?
A point which is not clear for me, are you dealing with Use case inheritance or diagram inheritance ? To tell the truth, I never used diagram inheritance and I am not sure if this is possible and the meaning of a such usage of inheritance.
I discuss with my friend our project and we are in a way to draw the sequence diagram ( UML 2).
He told me that the sequence diagram is drawn by the use case. It means that for each use case we should draw a Sequence Diagram.
Is it correct ?
Thank you for any suggestion.
Well, taken as dogma it is not correct. A sequence diagram (SD) shows the behavior of objects in the way they interchange messages (and also if needed their lifetime and some minor additional information). You "can" also use a sequence diagram to describe scenarios in use cases. But simply speaking, a SD is more technically oriented (class design/programmers) rather than business (business design/stakeholders). To visualize a use case scenario you're better off using activity diagrams (AD). And even better if you dive into BPMN (which brings ADs to a new level).
It is possible though, to convert ADs to SDs and vice versa without information loss (if you forget about the afore mentioned bits and pieces).
Now another point: you will not necessarily need a diagram for each use case. I found that often use cases are more easily (and even clearly) described in a textual way (see Cockburn or Bittner/Spence) rather than diagrammatically. Especially if you have UC scenarios that are very linear in their single actions. So you can leave out the AD for those and just fall back to simple text. You should further avoid describing UC scenarios in both ways (i.e. text and diagram) as this introduces unwanted redundancy (means you would need to maintain always both when changes happen; and they happen often; and people are lazy -> so which one holds the truth: text or diagram?).
Generally, as Thomas points out, use case detail is set forth in an activity diagram. As he also mentions, a use case scenario would use a sequence diagram, when necessary. A use case scenario is a single path through a use case.
Sequence diagrams aren't good at diagramming multiple simultaneous behaviors and multiple decision points, and use cases generally have both of these features in their behavior. Activity diagrams do these things very well. A single path through a use case, by definition, doesn't have simultaneous behaviors and decision points, so a sequence diagram is more appropriate.
Googling "use case scenario sequence diagram" gives a number of links that explain the use of sequence diagrams for use case scenarios in detail, of which this is an example.
UseCase is declaration of behavior (service or usefull behavior) of system which is executed by system with collaboration (interaction) with system's actors.
Any type of diagram defined in UML could by used to describe behavior on any level of abstraction. All of diagrams could be also used to describe both business or technical aspects of system.
UseCase is declaration of behavior, it means that UseCase does not define behavior at all. UML does not define scenarios of UseCase ,scenarios are usually defined in methodology not in UML.
If you need to describe behavior of system in context of UseCase you can use some of behavior diagrams defined in UML for each UseCase.