How to show "if" condition on a sequence diagram?
UmlSequence DiagramUml Problem Overview
I was wondering, how can one represent "if
" statement on a sequence diagram?
if (somethingShouldBeDone) {
// Do it
} else {
// Do something else
}
Can it be represented at all? The thing is ... in my code, fair amount of conditions are checked to determine a variety of actions. If i am going to show the actions, I'd like to explicitly state that actions are caused by particular events.
If possible create an image representation of a solution.
Uml Solutions
Solution 1 - Uml
If else condition, also called alternatives in UML terms can indeed be represented in sequence diagrams. Here is a link where you can find some nice resources on the subject http://www.ibm.com/developerworks/rational/library/3101.html
Solution 2 - Uml
If you paste
A.do() {
if (condition1) {
X.doSomething
} else if (condition2) {
Y.doSomethingElse
} else {
donotDoAnything
}
}
onto https://app.zenuml.com. It will generate a diagram for you.
Solution 3 - Uml
Very simple , using Alt fragment
Lets take an example of sequence diagram for an ATM machine.Let's say here you want
IF card inserted is valid then prompt "Enter Pin"....ELSE prompt "Invalid Pin"
Then here is the sequence diagram for the same
Hope this helps!
Solution 4 - Uml
In Visual Studio UML sequence this can also be described as fragments which is nicely documented here: https://msdn.microsoft.com/en-us/library/dd465153.aspx