class NormalizerBase

abstract class NormalizerBase implements SerializerAwareInterface, CacheableNormalizerInterface {
    use SerializerAwareTrait;
    
    /**
     * List of formats which supports (de-)normalization.
     *
     * @var string|string[]
     */
    protected $format;
    
    /**
     * {@inheritdoc}
     */
    public function supportsNormalization($data, ?string $format = NULL, array $context = []) : bool {
        // If we aren't dealing with an object or the format is not supported return
        // now.
        if (!is_object($data) || !$this->checkFormat($format)) {
            return FALSE;
        }
        $supported = array_keys($this->getSupportedTypes($format));
        return (bool) array_filter($supported, function ($name) use ($data) {
            return $data instanceof $name;
        });
    }
    
    /**
     * Implements \Symfony\Component\Serializer\Normalizer\DenormalizerInterface::supportsDenormalization()
     *
     * This class doesn't implement DenormalizerInterface, but most of its child
     * classes do. Therefore, this method is implemented at this level to reduce
     * code duplication.
     */
    public function supportsDenormalization($data, string $type, ?string $format = NULL, array $context = []) : bool {
        // If the format is not supported return now.
        if (!$this->checkFormat($format)) {
            return FALSE;
        }
        $supported = array_keys($this->getSupportedTypes($format));
        $subclass_check = function ($name) use ($type) {
            return (class_exists($name) || interface_exists($name)) && is_subclass_of($type, $name, TRUE);
        };
        return in_array($type, $supported) || array_filter($supported, $subclass_check);
    }
    
    /**
     * Checks if the provided format is supported by this normalizer.
     *
     * @param string $format
     *   The format to check.
     *
     * @return bool
     *   TRUE if the format is supported, FALSE otherwise. If no format is
     *   specified this will return TRUE.
     */
    protected function checkFormat($format = NULL) {
        if (!isset($format) || !isset($this->format)) {
            return TRUE;
        }
        return in_array($format, (array) $this->format, TRUE);
    }
    
    /**
     * Adds cacheability if applicable.
     *
     * @param array $context
     *   Context options for the normalizer.
     * @param $data
     *   The data that might have cacheability information.
     */
    protected function addCacheableDependency(array $context, $data) {
        if ($data instanceof CacheableDependencyInterface && isset($context[static::SERIALIZATION_CONTEXT_CACHEABILITY])) {
            $context[static::SERIALIZATION_CONTEXT_CACHEABILITY]->addCacheableDependency($data);
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public function getSupportedTypes(?string $format) : array {
        return [
            '*' => FALSE,
        ];
    }

}