How to show “if” condition on a sequence diagram?

Question

I was wondering, how can one represent \"if\" statement on a sequence diagram?

if (somethingShouldBeDone) {
       // Do it
} else {
       // D         


        

Answer 1

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