Not getting the rule field values through InstallData Object on click of custom button

I have created one userInput panel which has field like Host Name(is text field type) , UserName(is a rule field type) and Password(is a password field type). And we have created a custom button named as "Test Connection" which validate the user on the given host. For validating i have created TestConnection class which extend ButtonAction.
So on the click of button i am getting the all the values which are of text field type but not the rule or password field type at back-end.

Spec.xml

TestConnection.java

Not able to get the port, user and password field data from installData Object on click of button action.