code: public String checkAccess (Permission perm, Object context)
      {
          if (_permPolicy == null) {
              _permPolicy = createPermissionPolicy();
          }
          return _permPolicy.checkAccess(perm, context);
      }
docs: Checks whether or not this client has the specified permission.
  
  @return null if the user has access, a fully-qualified translatable message string
  indicating the reason for denial of access.
  
  @see ClientObject.PermissionPolicy