Read only for condition and other than admin role

Hi All,

 I used Read only for condition in RTC 4.0.0.1.

If attribute A has "GHOST" value then  that work item should be read only. This part is working fine.

 Along with this I want this work item writable to admin process role.

 If ( workItem.getValue(A) == "GHOST" && Role != Admin) then  Read only = true;

 I am not getting how to check contributers role in program.

 please any one suggest which method should be called and how?

 Thanks,

Kavita