Doctrine\ODM\MongoDB\Mapping\ClassMetadataFactory::doLoadMetadata PHP Method

    protected function doLoadMetadata($class, $parent, $rootEntityFound, array $nonSuperclassParents = array())
    {
        /** @var $class ClassMetadata */
        /** @var $parent ClassMetadata */
        if ($parent) {
            $class->setInheritanceType($parent->inheritanceType);
            $class->setDiscriminatorField($parent->discriminatorField);
            $class->setDiscriminatorMap($parent->discriminatorMap);
            $class->setDefaultDiscriminatorValue($parent->defaultDiscriminatorValue);
            $class->setIdGeneratorType($parent->generatorType);
            $this->addInheritedFields($class, $parent);
            $this->addInheritedRelations($class, $parent);
            $this->addInheritedIndexes($class, $parent);
            $this->setInheritedShardKey($class, $parent);
            $class->setIdentifier($parent->identifier);
            $class->setVersioned($parent->isVersioned);
            $class->setVersionField($parent->versionField);
            $class->setLifecycleCallbacks($parent->lifecycleCallbacks);
            $class->setAlsoLoadMethods($parent->alsoLoadMethods);
            $class->setChangeTrackingPolicy($parent->changeTrackingPolicy);
            $class->setWriteConcern($parent->writeConcern);
            $class->setFile($parent->getFile());
            if ($parent->isMappedSuperclass) {
                $class->setCustomRepositoryClass($parent->customRepositoryClassName);
            }
        }
        // Invoke driver
        try {
            $this->driver->loadMetadataForClass($class->getName(), $class);
        } catch (\ReflectionException $e) {
            throw MappingException::reflectionFailure($class->getName(), $e);
        }
        $this->validateIdentifier($class);
        if ($parent && $rootEntityFound && $parent->generatorType === $class->generatorType) {
            if ($parent->generatorType) {
                $class->setIdGeneratorType($parent->generatorType);
            }
            if ($parent->generatorOptions) {
                $class->setIdGeneratorOptions($parent->generatorOptions);
            }
            if ($parent->idGenerator) {
                $class->setIdGenerator($parent->idGenerator);
            }
        } else {
            $this->completeIdGeneratorMapping($class);
        }
        if ($parent && $parent->isInheritanceTypeSingleCollection()) {
            $class->setDatabase($parent->getDatabase());
            $class->setCollection($parent->getCollection());
        }
        $class->setParentClasses($nonSuperclassParents);
        if ($this->evm->hasListeners(Events::loadClassMetadata)) {
            $eventArgs = new LoadClassMetadataEventArgs($class, $this->dm);
            $this->evm->dispatchEvent(Events::loadClassMetadata, $eventArgs);
        }
    }