// We weren't able to integrate this node into the existing
// hierarchy; we have to dig deeper, until we either (1)
// find a match, or (2) reach a root; type is INHERIT,
// unless (by chance) there's something specified in an
// entry on grantOrDenyMap.
IAuthorizationPrincipal principal = authService.newPrincipal(group);
Assignment.Type assignmentType = getAssignmentType(principal, owner, activity, target);
parent = new Assignment(principal.getPrincipalString(), bean, assignmentType);
parent.addChild(a);
placeInHierarchy(parent, hierarchy, owner, activity, target);
}