izzum\statemachine\persistence\MongoDB::processGetState PHP Method

    public function processGetState(Identifier $identifier)
    {
        $state = null;
        try {
            //check if indexes exists every x times this method is called
            $this->checkAndCreateIndexesIfNecessary(500);
            //find the state
            //https://php.net/manual/en/mongocollection.findone.php
            $query = array("entity_id" => $identifier->getEntityId(), "machine" => $identifier->getMachine());
            $data = $this->getClient()->izzum->states->findOne($query);
            if ($data) {
                $state = $data['state'];
            }
        } catch (\Exception $e) {
            throw new Exception(sprintf('getting current state failed: [%s]', $e->getMessage()), Exception::PERSISTENCE_LAYER_EXCEPTION);
        }
        if (!$state) {
            throw new Exception(sprintf('no state found for [%s]. Did you "$machine->add()" it to the persistence layer?', $identifier->getId(true)), Exception::PERSISTENCE_LAYER_EXCEPTION);
        }
        return $state;
    }