title: How to show "if" condition on a sequence diagram?
body: <p>I was wondering, how can one represent "<code>if</code>" statement on a sequence diagram?</p>
  
  <pre><code>if (somethingShouldBeDone) {
         // Do it
  } else {
         // Do something else
  }
  </code></pre>
  
  <p>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.</p>
  
  <p>If possible create an image representation of a solution.</p>