Method displayList

/**
 * Execute and display a template script.
 *
 * @param   array|null  $items  Array of items
 *
 * @return  string
 *
 * @since   4.0.0
 */
public function displayList(array $items = null)
{
    /** @var \Joomla\CMS\MVC\Model\ListModel $model */
    $model = $this->getModel();
    // Get page query
    $currentUrl = Uri::getInstance();
    $currentPageDefaultInformation = ['offset' => 0, 'limit' => 20];
    $currentPageQuery = $currentUrl->getVar('page', $currentPageDefaultInformation);
    if ($items === null) {
        $items = [];
        foreach ($model->getItems() as $item) {
            $items[] = $this->prepareItem($item);
        }
    }
    $pagination = $model->getPagination();
    // Check for errors.
    if (\count($errors = $this->get('Errors'))) {
        throw new GenericDataException(implode("\n", $errors), 500);
    }
    if ($this->type === null) {
        throw new \RuntimeException('Content type missing');
    }
    // Set up links for pagination
    $totalItemsCount = $pagination->pagesTotal * $pagination->limit;
    $this->document->addMeta('total-pages', $pagination->pagesTotal)->addLink('self', (string) $currentUrl);
    // Check for first and previous pages
    if ($pagination->limitstart > 0) {
        $firstPage = clone $currentUrl;
        $firstPageQuery = $currentPageQuery;
        $firstPageQuery['offset'] = 0;
        $firstPage->setVar('page', $firstPageQuery);
        $previousPage = clone $currentUrl;
        $previousPageQuery = $currentPageQuery;
        $previousOffset = $currentPageQuery['offset'] - $pagination->limit;
        $previousPageQuery['offset'] = $previousOffset >= 0 ? $previousOffset : 0;
        $previousPage->setVar('page', $previousPageQuery);
        $this->document->addLink('first', $this->queryEncode((string) $firstPage))->addLink('previous', $this->queryEncode((string) $previousPage));
    }
    // Check for next and last pages
    if ($pagination->limitstart + $pagination->limit < $totalItemsCount) {
        $nextPage = clone $currentUrl;
        $nextPageQuery = $currentPageQuery;
        $nextOffset = $currentPageQuery['offset'] + $pagination->limit;
        $nextPageQuery['offset'] = $nextOffset > $pagination->pagesTotal * $pagination->limit ? $pagination->pagesTotal - $pagination->limit : $nextOffset;
        $nextPage->setVar('page', $nextPageQuery);
        $lastPage = clone $currentUrl;
        $lastPageQuery = $currentPageQuery;
        $lastPageQuery['offset'] = ($pagination->pagesTotal - 1) * $pagination->limit;
        $lastPage->setVar('page', $lastPageQuery);
        $this->document->addLink('next', $this->queryEncode((string) $nextPage))->addLink('last', $this->queryEncode((string) $lastPage));
    }
    $eventData = ['type' => OnGetApiFields::LIST, 'fields' => $this->fieldsToRenderList, 'context' => $this->type];
    $event = new OnGetApiFields('onApiGetFields', $eventData);
    /** @var OnGetApiFields $eventResult */
    $eventResult = Factory::getApplication()->getDispatcher()->dispatch('onApiGetFields', $event);
    $collection = (new Collection($items, $this->serializer))->fields([$this->type => $eventResult->getAllPropertiesToRender()]);
    if (!empty($this->relationship)) {
        $collection->with($this->relationship);
    }
    // Set the data into the document and render it
    $this->document->setData($collection);
    return $this->document->render();
}