groovy - Jenkins: hudson.model.User.current() returns SYSTEM -

I'm currently running the following command to get the logged in user in Jenkins.

  Hudson.Model.USER. (.)  

But, the result I'm getting is "System". Does this mean that Jenkins has all the systems in the form of a user and if this is the case then what is the following approach, the only way to trigger the user to create a URIID?

 for  (Hudson.Model. Causes: buildcues) {UserBuild = reason.getUserName ()} Actually, I created buildCaption.jelly in Jenkins I am trying to edit, so that only the user who triggers the build can cancel the build. And I'm stuck at a point in which I'm currently required to get user's user logged in, so that I can check whether it is similar to the user who started the construction. Any ideas, please suggest thanks in advance.