presto-main/src/main/java/io/prestosql/sql/planner/iterative/rule/DetermineJoinDistributionType.java/DetermineJoinDistributionType/DetermineJoinDistributionType
class DetermineJoinDistributionType:    public DetermineJoinDistributionType(CostComparator costComparator, TaskCountEstimator taskCountEstimator)
    {
        this.costComparator = requireNonNull(costComparator, "costComparator is null");
        this.taskCountEstimator = requireNonNull(taskCountEstimator, "taskCountEstimator is null");
    }