class IdentityAggregator extends SeekingAggregator implements FieldIndexAggregator {

    @Override
    public Key apply(SortedKeyValueIterator<Key,Value> itr) throws IOException {
        Key key = itr.getTopKey();
        Text row = key.getRow();
        ByteSequence pointer = parsePointer(key.getColumnQualifierData());
        while (itr.hasTop() && samePointer(row, pointer, itr.getTopKey()))
            itr.next();
        
        return TLD.buildParentKey(row, pointer, parseFieldNameValue(key.getColumnFamilyData(), key.getColumnQualifierData()), key.getColumnVisibility(),
                        key.getTimestamp());
    }

    public  IdentityAggregator(Set<String> fieldsToKeep, EventDataQueryFilter filter, int maxNextCount);
    public  IdentityAggregator(Set<String> fieldsToKeep, EventDataQueryFilter filter);
    public  IdentityAggregator(Set<String> fieldsToKeep);
    public  IdentityAggregator();

}