@Override
public boolean next(RecordIdentifier recordIdentifier, OrcStruct prev) throws IOException {
boolean keysSame = true;
while (keysSame && primary != null) {
// The primary's nextRecord is the next value to return
OrcStruct current = primary.nextRecord;
recordIdentifier.set(primary.key);
// Advance the primary reader to the next record
primary.next(extraValue);
// Save the current record as the new extraValue for next time so that
// we minimize allocations
extraValue = current;
// now that the primary reader has advanced, we need to see if we
// continue to read it or move to the secondary.
if (primary.nextRecord == null || primary.key.compareTo(secondaryKey) > 0) {
// if the primary isn't done, push it back into the readers
if (primary.nextRecord != null) {
readers.put(primary.key, primary);
}
// update primary and secondaryKey
Map.Entry<ReaderKey, ReaderPair> entry = readers.pollFirstEntry();
if (entry != null) {
primary = entry.getValue();
if (readers.isEmpty()) {
secondaryKey = null;
} else {
secondaryKey = readers.firstKey();
}
} else {
primary = null;
}
}
// if this transaction isn't ok, skip over it
if (!validTxnList.isTxnValid(((ReaderKey) recordIdentifier).getCurrentTransactionId())) {
continue;
}
// if we are collapsing, figure out if this is a new row
if (collapse) {
keysSame = prevKey.compareRow(recordIdentifier) == 0;
if (!keysSame) {
prevKey.set(recordIdentifier);
}
} else {
keysSame = false;
}
// set the output record by fiddling with the pointers so that we can
// avoid a copy.
prev.linkFields(current);
}
return !keysSame;
}
