title: WiX: Abort installation if a specific executable is not in the PATH
body: <p>I'm currently packaging software with WiX that needs Java to run. Therefore I'd like to check during installation if <code>java.exe</code> is somewhere in the <code>PATH</code> and abort if it could not be found. The solution in <a href="http://sourceforge.net/mailarchive/message.php?msg_id=23451655" rel="nofollow">http://sourceforge.net/mailarchive/message.php?msg_id=23451655</a> comes close to my needs, but instead of searching the registry, I'd like to look for the dependency in the directories in the <code>PATH</code> variable.</p>
  
  <p>Is this easily possible with WiX? If not, is it possible to set the value of a property based on the return value of a custom action. I could then write a batch script that looks for Java and sets the property for the <code>&lt;Condition&gt;</code> accordingly.</p>