lib/Doctrine/ODM/CouchDB/Mapping/ClassMetadataFactory.php
protected function loadMetadata($className)
    {
        if (class_exists($className)) {
            return parent::loadMetadata($className);
        }
        throw MappingException::classNotFound($className);
    }
protected function loadMetadata($className)
    {
        if (class_exists($className)) {
            return parent::loadMetadata($className);
        }
        throw MappingException::classNotFound($className);
    }
Loads the metadata of the class in question and all it's ancestors whose metadata
is still not loaded.

@param string $className The name of the class for which the metadata should get loaded.
@return array
@throws MappingException