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package com.salesforce.phoenix.iterate;
import static com.salesforce.phoenix.query.QueryConstants.*;
import java.sql.SQLException;
import com.salesforce.phoenix.expression.aggregator.Aggregators;
import com.salesforce.phoenix.schema.tuple.SingleKeyValueTuple;
import com.salesforce.phoenix.schema.tuple.Tuple;
import com.salesforce.phoenix.util.KeyValueUtil;
public class UngroupedAggregatingResultIterator extends GroupedAggregatingResultIterator {
private boolean hasRows = false;
public UngroupedAggregatingResultIterator( PeekingResultIterator resultIterator, Aggregators aggregators) {
super(resultIterator, aggregators);
}
@Override
public Tuple next() throws SQLException {
Tuple result = super.next();
// Ensure ungrouped aggregregation always returns a row, even if the underlying iterator doesn't.
if (result == null && !hasRows) {
// Generate value using unused ClientAggregators
byte[] value = aggregators.toBytes(aggregators.getAggregators());
result = new SingleKeyValueTuple(
KeyValueUtil.newKeyValue(UNGROUPED_AGG_ROW_KEY,
SINGLE_COLUMN_FAMILY,
SINGLE_COLUMN,
AGG_TIMESTAMP,
value));
}
hasRows = true;
return result;
}
}