...
If your component needs an output called "employee-greeting-email-text", you can check that it has been defined in the action sequence by calling isDefinedOutput() with "employee-greeting-email-text" as the argument.
Your validateAction method would now look like this
...
Notice that we are only checking to see if the input has been defined and we are not trying to get the input value.
The validateAction of the EmailComponent looks like this:
...