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 you paste

A.do() {
  if (condition1) {
   X.doSomething
  } else if (condition2) {
   Y.doSomethingElse
  } else {
   donotDoAnything
  }
}

onto https://www.zenuml.com. It will generate a diagram for you.