class JsonApiDocumentTopLevel

class JsonApiDocumentTopLevel {
    
    /**
     * The data to normalize.
     *
     * @var \Drupal\jsonapi\JsonApiResource\ResourceIdentifierInterface|\Drupal\jsonapi\JsonApiResource\Data|\Drupal\jsonapi\JsonApiResource\ErrorCollection|\Drupal\Core\Field\EntityReferenceFieldItemListInterface
     */
    protected $data;
    
    /**
     * The metadata to normalize.
     *
     * @var array
     */
    protected $meta;
    
    /**
     * The links.
     *
     * @var \Drupal\jsonapi\JsonApiResource\LinkCollection
     */
    protected $links;
    
    /**
     * The includes to normalize.
     *
     * @var \Drupal\jsonapi\JsonApiResource\IncludedData
     */
    protected $includes;
    
    /**
     * Resource objects that will be omitted from the response for access reasons.
     *
     * @var \Drupal\jsonapi\JsonApiResource\OmittedData
     */
    protected $omissions;
    
    /**
     * Instantiates a JsonApiDocumentTopLevel object.
     *
     * @param \Drupal\jsonapi\JsonApiResource\TopLevelDataInterface|\Drupal\jsonapi\JsonApiResource\ErrorCollection $data
     *   The data to normalize. It can be either a ResourceObject, or a stand-in
     *   for one, or a collection of the same.
     * @param \Drupal\jsonapi\JsonApiResource\IncludedData $includes
     *   A JSON:API Data object containing resources to be included in the
     *   response document or NULL if there should not be includes.
     * @param \Drupal\jsonapi\JsonApiResource\LinkCollection $links
     *   A collection of links to resources related to the top-level document.
     * @param array $meta
     *   (optional) The metadata to normalize.
     */
    public function __construct($data, IncludedData $includes, LinkCollection $links, array $meta = []) {
        assert($data instanceof TopLevelDataInterface || $data instanceof ErrorCollection);
        assert(!$data instanceof ErrorCollection || $includes instanceof NullIncludedData);
        $this->data = $data instanceof TopLevelDataInterface ? $data->getData() : $data;
        $this->includes = $includes->getData();
        $this->links = $data instanceof TopLevelDataInterface ? $data->getMergedLinks($links->withContext($this)) : $links->withContext($this);
        $this->meta = $data instanceof TopLevelDataInterface ? $data->getMergedMeta($meta) : $meta;
        $this->omissions = $data instanceof TopLevelDataInterface ? OmittedData::merge($data->getOmissions(), $includes->getOmissions()) : $includes->getOmissions();
    }
    
    /**
     * Gets the data.
     *
     * @return \Drupal\jsonapi\JsonApiResource\Data|\Drupal\jsonapi\JsonApiResource\ErrorCollection
     *   The data.
     */
    public function getData() {
        return $this->data;
    }
    
    /**
     * Gets the links.
     *
     * @return \Drupal\jsonapi\JsonApiResource\LinkCollection
     *   The top-level links.
     */
    public function getLinks() {
        return $this->links;
    }
    
    /**
     * Gets the metadata.
     *
     * @return array
     *   The metadata.
     */
    public function getMeta() {
        return $this->meta;
    }
    
    /**
     * Gets a JSON:API Data object of resources to be included in the response.
     *
     * @return \Drupal\jsonapi\JsonApiResource\IncludedData
     *   The includes.
     */
    public function getIncludes() {
        return $this->includes;
    }
    
    /**
     * Gets an OmittedData instance containing resources to be omitted.
     *
     * @return \Drupal\jsonapi\JsonApiResource\OmittedData
     *   The omissions.
     */
    public function getOmissions() {
        return $this->omissions;
    }

}