How to get Event Adapter from a repository?

SchedulableListener.php

class SchedulableListener extends MappedEventSubscriber
{
    // ...

    public function getRecurrenceRuleClass(SchedulableAdapter $ea, $class)
    {
        return isset($this->configurations['schedulable']['recurrenceRuleClass']) ?
            $this->configurations['schedulable']['recurrenceRuleClass'] :
            $ea->getDefaultRecurrenceRuleClass();
    }
}

SchedulableRepository.php

class SchedulableRepository extends EntityRepository
{
    public function findInDateRange($startDate, $endDate)
    {
        $objectMeta = $this->getClassMetadata();
        $ea = // How do I access the Adapter here? (BaseAdapterORM)
        $ruleClass  = $listener->getRecurrenceRuleClass($ea, $objectMeta->name);
    }
}