Sequence Diagram

[swjam]

How do I depict decision-branching in a sequence diagram? Can anyone provide a simple example (maybe a simple drawing) where an object makes two different calls /sends two different messages or events depending on a decision within its function or thread of execution. Thank you!

I am a SysAdmin, I battle my own daemons.

[Brady Kelly]

I don't have any reference material with me, but as far as I recall you use a block with a guard condition around all the messages within each variant of the decision outcome.

[Virtual Coder]

DenClancy wrote:

How do I depict decision-branching in a sequence diagram?

There is no IF or ELSE in a (UML) sequence diagram, AFAIK. If you want to depict decision-branching just draw multiple sequence diagrams, one for each branch.

[CPallini]

perhaps you need an activity diagram.

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.

[duaatul]

Exactly. I don't think Sequence diagrams are supposed to depict if / else. Infact, for any if and else you need to have a new sequence diagram. Thats the whole intenet of a sequence diagram.