class MultiPathMapper implements Mapper {

    @Override
    public Object keyForSource(RowProxy source) {
        Map<String, Object> keyMap = new HashMap<>(pathMappers.size() * 2);
        for (Entry<String, Mapper> e : pathMappers.entrySet()) {
            keyMap.put(e.getKey(), e.getValue().keyForSource(source));
        }

        return keyMap;
    }

    public  MultiPathMapper(Map<String, Mapper> pathMappers);

}