What does an arrowhead inside a circle mean in the UML?
Basically I think that my comment above says it all. However, there are exceptions. For example in Enterprise Architect you can stereotype connectors and have any rendering you want, except for the two elements to be connected with a line. So you can create any kind of art along the connector. But then again, if you stereotype something it is valid only in a certain domain and needs extra documentation. If so in your case the author is to blame in any case for not providing that information.
It is an invalid UML symbol and nothing offical.
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I have been trying to understand it but I couldn't. Can someone explain this shortly? Is there some problem with this UML diagram? If there is, where?
I thought that instead of extending arrows there might be a generalization for the pic, video, tag names, and feeling use cases. And I think that included arrows should have been dashed. Are these true? Thank you already.
You can not understand this since it is absolute nonsense. This is some semi-activity diagram. A use case is about actor goals, not how to do something. Please give the author of that a heavy kick in the rear. Or if you not that rude as myself (being a pacifist with empasis on fist - haha) just encourage them otherwise to start learning about use cases.
As always I recommend reading Bittner/Spence about use cases.
The following aspects of the diagram violate the UML specifications:
The boundary box shall represent a system (e.g. Facebook), not a function (Add Status).
Keywords include and extend shall be written in guillemets: «include», «extend».
The «include» arrows shall be dashed.
The «include» arrows shall have open arrow-heads.
To apply the use case technique in a project, the team shall agree on a specific methodology and/or philosophy. UML doesn't offer this, it is just a language (despite some definitions in the UML specification that point in a certain direction). Therefore, I will not give my opinion on whether this is a proper way of use case modeling.
With regard to generalization versus extension: both are possible in this case. If "Add Status" would mean: add pic or add video or etc., then a generalization would be more appropriate. The extension suggests that "Add Status" means: add pic and/or video and/or etc. In other words, each extending use case extends the original with additional capabilities.
If my class (interface) has no fields, should I leave white space to make it obvious that there is to state?
With whitespace:
No whitespace:
I'd use with whitespace. I've seen some examples on the web like this (https://www.ibm.com/developerworks/rational/library/content/RationalEdge/sep04/bell/). In Figure 10, The Person interface has no methods, but the space to put methods is present.
You can do it both ways. Compartments can be set ad libitum. Use whatever fits your taste best. You should however setup modeling rules that constraint the use of compartments to whatever you think might be the best. The UML spec e.g. uses this on p. 16:
Within such a diagram, all of the metaclasses described in that clause are depicted with their attribute compartments, while metaclasses whose definition appears in another clause are depicted with just their headers and no compartments.
And some more examples on pp. 193.
P.S. I have just checked what EA shows in case and it will not show an empty compartment but completely suppress it.
I'am creating an statechart diagram in StarUML and I want to show the name of choice elements in the diagram, but I don't know how to do it without adding a text annotation.
Do you know if it is possible?
Thanks!
(...)
Showing names of control nodes (including decision, merge, ...) diagram is not supported. It was never supported in previous versions, even in V1. Typically just show the guards of the control flows connected to the decision node, instead of showing the name of decision node. At this time, we recommend to use "Text" or "Note" annotation.
(...)
Thanks,
StarUML Team
This was the answer about the same question in this forum. Take a look.
Agree with #Victor, I just add Text Element inside the Choice Element.
I'm very new to UML, especially use case diagrams. I attempted to draw a use case diagram for my application which includes a renter, a seller, and a general user. My renter and seller extend general user. I am having trouble with includes and extends. For example, When you view an office space, you can also see the reviews for it at the bottom of the page. As well as when a renter wants to write a review, he/she must do this on the view office space page. I am not sure if this is an extends or an include. Please correct me if I am wrong with any of my arrow directions. Also, is it okay to say that Renter and Seller include logging in?
As Jim states: I/E are for UCs, not for Actors. I assume you meant a generalization here, so both inherit from General User.
Some further observations:
Use verb-substantive for UCs titles
Think of the "use" in use cases. IOW: the added value. If you don't find it's added value, then it's no use case.
Avoid I/E in general. They often indicate that you try to use functional decomposition which is not the aim of a UC synthesis.
The relation you draw between the UCs is wrong in any case. There is no relation which has a filled triangle and is dotted. You probably meant to use some <<include>> dependency (with an open arrow). But as said above: avoid it. Just create an association to the actors. It's sufficient to just draw one between Reviews and General User as Renter will inherit the relation.
Login/out are no UCs (no added value). The are constraints to other UC (write {must be logged in} and attach to the connector)
You generally should not model login use cases, as they don't directly help the user accomplish anything he or she cares about.
Includes and extends are relationships between use use cases, not actors. The UML 2.5 specification says:
An extension is:
A relationship from an extending UseCase to an extended UseCase that specifies how and when the behavior defined in the extending UseCase can be inserted into the behavior defined in the extended UseCase.
An include is:
An Include relationship specifies that a UseCase contains the behavior defined in another UseCase.
A generalization / specialization relationship between actors is perfectly fine. That's just a generalization arrow. (e.g., a solid line with a hollow arrow head.)
I am looking for the best solution to draw mapping diagram in EA. I find that composite structure diagram might suits my needs. I have even found good example of such diagram on the net:
(Original source: http://www.dthomas.co.uk/dtalm/images/eshot/test/data_map.JPG)
This diagram was fully created in EA (as author claims). However I am not able to attach 'represents' relation to the attribute. Does any one know how to do that (I am talking about those little open squares in class representations).
Thank you in advance for your answer.
Good question!
I found your answer in Google Groups:
draw a dependency from one class to the other.
Then Right Click on the left side of the dependency and chose Link to Element Feature, chose Attribut and then select your attribute.
On the right side the same procedure.
On my EA 10 (Corp.Ed.), I was able to reproduce the described steps. See attached image.
I just downloaded EA and created a simple example by creating :
one class with a part
one collaboration with also a part
one 'represents' relation by using the command highlighted
Hoping it helps,
EBR.
PS: it is out of the scope of your question but what is the goal of this mapping diagram? It is just curiosity..