class Athena::ORM::Events::OnFlushEventArgs
inherits Athena::ORM::Events::ManagerEventArgs

Emitted by AORM::EntityManager#flush once the changes to every managed entity have been computed, before anything is written.

Listeners can inspect what the flush is about to do through the unit of work:

dispatcher = AED::EventDispatcher.new

dispatcher.listener AORM::Events::OnFlushEventArgs do |event|
  uow = event.entity_manager.unit_of_work

  uow.scheduled_entity_insertions.each { |entity| Log.info { "Inserting #{entity.class}" } }
  uow.scheduled_entity_updates.each { |entity| Log.info { "Updating #{entity.class}: #{uow.entity_changeset(entity).keys}" } }
  uow.scheduled_entity_deletions.each { |entity| Log.info { "Deleting #{entity.class}" } }
end

em = AORM::EntityManager.new connection, dispatcher

It's emitted on every flush, even when there is nothing to write. In that case the flush ends once the event is dispatched, without writing anything a listener persists or changes. Only the event dispatcher receives it; there is no lifecycle callback for it.

Change sets are computed before the event is dispatched. A listener that persists an entity also computes its change set via AORM::UnitOfWork#compute_change_set, and one that changes a managed entity recomputes it via AORM::UnitOfWork#recompute_single_entity_change_set.