public function getEntityBuilder($className = null, ClassMetadata $classMetadata = null)
    {
        $builder = new Entity\Builder($this->getMapper(), $this->getFieldManager());

        if ($className !== null) {
            $builder->setClass($className);
        }

        if ($classMetadata !== null) {
            $builder->setClassMetadata($classMetadata);
        }

        return $builder;
    }