code: private String handleCompositeColumnName(final String columnName) {
          final String columnKey = columnName.substring(columnName.lastIndexOf(":") + 1);
          return columnKey.equals("") ? columnName : columnKey;
      }
docs: Return the actual column name from a composite column name.
  <p/>
  i.e. key_1:key_2:key_3:column_name
  
  @param columnName
  @return