try {
AccessControlManager acm = session.getAccessControlManager();
AccessControlList acl = (AccessControlList)acm.getPolicies(path)[0];
AccessControlEntry entry = pick(acl, principal);
acl.removeAccessControlEntry(entry);
Privilege[] privs = enabled ? includePrivilege(acm, entry.getPrivileges(), permission) : excludePrivilege(entry.getPrivileges(),
permission);
acl.addAccessControlEntry(entry.getPrincipal(), privs);
} catch (Exception e) {