code: private TableAlias createTableAlias(ClassDescriptor aCld, String aPath, String aUserAlias, List hints)
      {
  		if (aUserAlias == null)
  		{
  			return createTableAlias(aCld, hints, aPath);
  		}
  		else
  		{
  			return createTableAlias(aCld, hints, aUserAlias + ALIAS_SEPARATOR + aPath);
  		}
      }
docs: Create a TableAlias for path or userAlias
  @param aCld
  @param aPath
  @param aUserAlias
  @param hints a List os Class objects to be used as hints for path expressions
  @return TableAlias