presto-main/src/main/java/io/prestosql/execution/scheduler/SourcePartitionedScheduler.java/SourcePartitionedScheduler/SourcePartitionedScheduler
class SourcePartitionedScheduler:    private SourcePartitionedScheduler(
            SqlStageExecution stage,
            PlanNodeId partitionedNode,
            SplitSource splitSource,
            SplitPlacementPolicy splitPlacementPolicy,
            int splitBatchSize,
            boolean groupedExecution)
    {
        this.stage = requireNonNull(stage, "stage is null");
        this.partitionedNode = requireNonNull(partitionedNode, "partitionedNode is null");
        this.splitSource = requireNonNull(splitSource, "splitSource is null");
        this.splitPlacementPolicy = requireNonNull(splitPlacementPolicy, "splitPlacementPolicy is null");

        checkArgument(splitBatchSize > 0, "splitBatchSize must be at least one");
        this.splitBatchSize = splitBatchSize;
        this.groupedExecution = groupedExecution;
    }