Get rolebased permissions programmaticly serverside?

I want to check if user has permission for the actions he takes, even if one of his roles is ignored. For that I need to check in advisor if a role has permission to take a certain action. I think i need to use a call to "https://jazzserver/service/com.ibm.team.process.internal.service.web.IProcessWebUIService/permissions?context=1&processAreaContext=1&processAreaItemId=id&roleId=role", but i don't really know how to call that from inside the java API. Any help or better solutions are highly appreciated.

Example use case: every teammember has role creator but it should only be applicable if user is creator of workitem, if not I need to check if maybe user is allowed to take the intended actions anyway because he's admin or something.