private void checkAccess(Job job, JobACL jobOperation) throws IOException {

            UserGroupInformation callerUGI;
            callerUGI = UserGroupInformation.getCurrentUser();

            if (!job.checkAccess(callerUGI, jobOperation)) {
                throw new IOException(new AccessControlException("User "
                        + callerUGI.getShortUserName() + " cannot perform operation "
                        + jobOperation.name() + " on " + job.getID()));
            }
        }
This module is responsible for talking to the
JobClient (user facing).
history-server/src/main/java/net/qihoo/hbox/jobhistory/HistoryClientService.java