class InterpolationVariableCollector {

    public Map<InterpolationVariable, Integer> getMap() {
        final HashMap<InterpolationVariable, Integer> result = new HashMap<InterpolationVariable, Integer>();

        int index = 0;
        for (Integer integer : byColumn.keySet()) {
            result.put(byColumn.get(integer),
                       index);
            index++;
        }

        return result;
    }

    public  InterpolationVariableCollector(final Map<InterpolationVariable, Integer> map,
                                          final String defaultType);
    public  InterpolationVariableCollector(final Map<InterpolationVariable, Integer> map);

}