HydraApi.php
private function getTypeReferenceIri($type)
    {
        if (null === $type) {
            return null;
        }

        if (array_key_exists($type, self::$typeMap)) {
            return self::$typeMap[$type];
        }

        if ($this->hasNormalizer($type)) {
            return $this->getNormalizer($type)->getTypeIri();
        }

        $metadata = $this->metadata->getMetadataFor($type);

        if (null === $metadata) {
            // TODO Improve this
            throw new \Exception('Found invalid type: ' . $type);
        }

        if ($metadata->isExternalReference()) {
            return $metadata->getIri();
        } else {
            return 'vocab:' . $metadata->getIri();
        }
    }
private function getTypeReferenceIri($type)
    {
        if (null === $type) {
            return null;
        }

        if (array_key_exists($type, self::$typeMap)) {
            return self::$typeMap[$type];
        }

        if ($this->hasNormalizer($type)) {
            return $this->getNormalizer($type)->getTypeIri();
        }

        $metadata = $this->metadata->getMetadataFor($type);

        if (null === $metadata) {
            // TODO Improve this
            throw new \Exception('Found invalid type: ' . $type);
        }

        if ($metadata->isExternalReference()) {
            return $metadata->getIri();
        } else {
            return 'vocab:' . $metadata->getIri();
        }
    }
Get the (compact) IRI to reference the specified type

@param string|null $type The type to reference.

@return string|null The IRI corresponding to the type.