| Sequence diagram: upward messages [message #744736] |
Sat, 22 October 2011 05:52  |
Eclipse User |
|
|
|
Hello colleagues,
I'm working with Papyrus UML Sequence diagram and can not understand: why it's impossible to create messages directed upwards? Is it a bug or feature? Suppose we have very simple example including two lifelines and one asynchronous message (see picture attached). The initial diagram is in the top-left. When I drag arow end downwards (bottom-left figure), it's OK. But when I drag it upwards, this is impossibe, mouse cursor becomes restrictive (see top-right figure). However, if to move the whole right lifeline upwards, diagram editor allows this, and we get message directed upwards (bottom-right figure).
Does anyone knows why is this? And is there a way to create messages directed upwards?
Attachment: sequence.png
(Size: 11.53KB, Downloaded 340 times)
[Updated on: Sat, 22 October 2011 23:27] by Moderator |
|
|
|
| Re: Sequence diagram: upward messages [message #753742 is a reply to message #747289] |
Fri, 28 October 2011 10:47  |
| Eclipse User |
|
|
|
Hello Yang,
Thanks for answer.
LiuYang wrote on Sun, 23 October 2011 21:57Message has target and source lifeline, target lifeline can only receive the message after source lifeline send it out.
Yes, we can not receive message before it is sent, but who said that lifelines are synchronized by ordinate - purely graphical characteristic? The only thing that synchronizes lifelines is message - if it links two lifelines then send and receive points on them are certainly in timing relationship (if disregard transmit time this relationship is equality). I don't see any obstacle for this points to be located anywhere in the diagram graphical field.
And when we read timing information from the model (as you wrote) we usually fetch only events covered by one lifeline, otherwise events set will be a mix of different lifelines events which is hardly to work with.
So for now I still don't understand the behavior described. So please if there are more ideas please suggest, thank you.
|
|
|
Powered by
FUDForum. Page generated in 1.05943 seconds
Home