throws AlreadyExistsException {
Assert.notNull(objectIdentity, "Object Identity required");
// Check this object identity hasn't already been persisted
if (retrieveObjectIdentityPrimaryKey(objectIdentity) != null) {
throw new AlreadyExistsException("Object identity '" + objectIdentity + "' already exists");
}
// Need to retrieve the current principal, in order to know who "owns" this ACL (can be changed later on)
Authentication auth = SecurityContextHolder.getContext().getAuthentication();
PrincipalSid sid = new PrincipalSid(auth);