ElementInterface.php

<?php

namespace Drupal\Core\Render\Element;

use Drupal\Component\Plugin\PluginInspectionInterface;

/**
 * Provides an interface for render element plugins.
 *
 * Render element plugins allow modules to declare their own Render API element
 * types and specify the default values for the properties. The values returned
 * by the getInfo() method of the element plugin will be merged with the
 * properties specified in render arrays. Thus, you can specify defaults for any
 * Render API keys, in addition to those explicitly documented by
 * \Drupal\Core\Render\ElementInfoManagerInterface::getInfo().
 *
 * Some render elements are specifically form input elements; see
 * \Drupal\Core\Render\Element\FormElementInterface for more information.
 *
 * The public API of these objects must be designed with security in mind as
 * render elements process raw user input.
 *
 * @see \Drupal\Core\Render\ElementInfoManager
 * @see \Drupal\Core\Render\Annotation\RenderElement
 * @see \Drupal\Core\Render\Element\RenderElement
 * @see plugin_api
 *
 * @ingroup theme_render
 */
interface ElementInterface extends PluginInspectionInterface, RenderCallbackInterface {
    
    /**
     * Returns the element properties for this element.
     *
     * @return array
     *   An array of element properties. See
     *   \Drupal\Core\Render\ElementInfoManagerInterface::getInfo() for
     *   documentation of the standard properties of all elements, and the
     *   return value format.
     */
    public function getInfo();
    
    /**
     * Sets a form element's class attribute.
     *
     * Adds 'required' and 'error' classes as needed.
     *
     * @param array $element
     *   The form element.
     * @param array $class
     *   Array of new class names to be added.
     */
    public static function setAttributes(&$element, $class = []);

}