code: @Override public Integer[] getUniqueIdentifierArray()
     {
        Integer[] result = new Integer[m_table.size()];
        int index = 0;
        for (Integer value : m_table.keySet())
        {
           result[index] = value;
           ++index;
        }
        return (result);
     }
docs: This method returns an array containing all of the unique identifiers
  for which data has been stored in the Var2Data block.
  
  @return array of unique identifiers