@Nonnull
  @ReturnsMutableCopy
  public ICommonsList <IUserGroup> getAllUserGroupsWithAssignedUser (@Nullable final String sUserID)
  {
    if (StringHelper.hasNoText (sUserID))
      return new CommonsArrayList <> ();

    return getAll (aUserGroup -> aUserGroup.containsUserID (sUserID));
  }
@ Nonnull @ ReturnsMutableCopy public ICommonsList < IUserGroup > getAllUserGroupsWithAssignedUser ( @ Nullable final String sUserID ) { if ( StringHelper . hasNoText ( sUserID ) ) return new CommonsArrayList < > ( ) ; return getAll ( aUserGroup -> aUserGroup . containsUserID ( sUserID ) ) ; }
Get a collection of all user groups to which a certain user is assigned to.

@param sUserID
The user ID to search
@return A non-<code>null</code>but may be empty collection with all
matching user groups.