izzum\statemachine\Identifier::toString PHP Method

    public function toString()
    {
        return get_class($this) . ' ' . $this->getId(true);
    }

 /**
  * {@inheritDoc}            
  */
 public function processGetState(Identifier $identifier)
 {
     $connection = $this->getConnection();
     $prefix = $this->getPrefix();
     try {
         $query = 'SELECT state FROM ' . $prefix . 'statemachine_entities WHERE machine = ' . ':machine AND entity_id = :entity_id';
         $machine = $identifier->getMachine();
         $entity_id = $identifier->getEntityId();
         $statement = $connection->prepare($query);
         $statement->bindParam(":machine", $machine);
         $statement->bindParam(":entity_id", $entity_id);
         $result = $statement->execute();
         if ($result === false) {
             throw new Exception($this->getErrorInfo($statement));
         }
     } catch (\Exception $e) {
         throw new Exception(sprintf('query for getting current state failed: [%s]', $e->getMessage()), Exception::PERSISTENCE_LAYER_EXCEPTION);
     }
     $row = $statement->fetch();
     if ($row === false) {
         throw new Exception(sprintf('no state found for [%s]. Did you "$machine->add()" it to the persistence layer?', $identifier->toString()), Exception::PERSISTENCE_LAYER_EXCEPTION);
         return State::STATE_UNKNOWN;
     }
     return $row['state'];
 }