class Link

class Link implements RenderableInterface {
    
    /**
     * The link generator.
     *
     * @var \Drupal\Core\Utility\LinkGeneratorInterface
     */
    protected $linkGenerator;
    
    /**
     * The text of the link.
     *
     * @var string
     */
    protected $text;
    
    /**
     * The URL of the link.
     *
     * @var \Drupal\Core\Url
     */
    protected $url;
    
    /**
     * Constructs a new Link object.
     *
     * @param string $text
     *   The text of the link.
     * @param \Drupal\Core\Url $url
     *   The url object.
     */
    public function __construct($text, Url $url) {
        $this->text = $text;
        $this->url = $url;
    }
    
    /**
     * Creates a Link object from a given route name and parameters.
     *
     * @param string $text
     *   The text of the link.
     * @param string $route_name
     *   The name of the route
     * @param array $route_parameters
     *   (optional) An associative array of parameter names and values.
     * @param array $options
     *   The options parameter takes exactly the same structure.
     *   See \Drupal\Core\Url::fromUri() for details.
     *
     * @return static
     */
    public static function createFromRoute($text, $route_name, $route_parameters = [], $options = []) {
        return new static($text, new Url($route_name, $route_parameters, $options));
    }
    
    /**
     * Creates a Link object from a given Url object.
     *
     * @param string|array|\Drupal\Component\Render\MarkupInterface $text
     *   The link text for the anchor tag as a translated string or render array.
     * @param \Drupal\Core\Url $url
     *   The Url to create the link for.
     *
     * @return static
     */
    public static function fromTextAndUrl($text, Url $url) {
        return new static($text, $url);
    }
    
    /**
     * Returns the text of the link.
     *
     * @return string
     */
    public function getText() {
        return $this->text;
    }
    
    /**
     * Sets the new text of the link.
     *
     * @param string $text
     *   The new text.
     *
     * @return $this
     */
    public function setText($text) {
        $this->text = $text;
        return $this;
    }
    
    /**
     * Returns the URL of the link.
     *
     * @return \Drupal\Core\Url
     */
    public function getUrl() {
        return $this->url;
    }
    
    /**
     * Sets the URL of this link.
     *
     * @param Url $url
     *   The URL object to set
     *
     * @return $this
     */
    public function setUrl(Url $url) {
        $this->url = $url;
        return $this;
    }
    
    /**
     * Generates the HTML for this Link object.
     *
     * Do not use this method to render a link in an HTML context. In an HTML
     * context, self::toRenderable() should be used so that render cache
     * information is maintained. However, there might be use cases such as tests
     * and non-HTML contexts where calling this method directly makes sense.
     *
     * @return \Drupal\Core\GeneratedLink
     *   The link HTML markup.
     *
     * @see \Drupal\Core\Link::toRenderable()
     */
    public function toString() {
        return $this->getLinkGenerator()
            ->generateFromLink($this);
    }
    
    /**
     * {@inheritdoc}
     */
    public function toRenderable() {
        return [
            '#type' => 'link',
            '#url' => $this->url,
            '#title' => $this->text,
        ];
    }
    
    /**
     * Returns the link generator.
     *
     * @return \Drupal\Core\Utility\LinkGeneratorInterface
     *   The link generator
     */
    protected function getLinkGenerator() {
        if (!isset($this->linkGenerator)) {
            $this->linkGenerator = \Drupal::service('link_generator');
        }
        return $this->linkGenerator;
    }
    
    /**
     * Sets the link generator service.
     *
     * @param \Drupal\Core\Utility\LinkGeneratorInterface $generator
     *   The link generator service.
     *
     * @return $this
     */
    public function setLinkGenerator(LinkGeneratorInterface $generator) {
        $this->linkGenerator = $generator;
        return $this;
    }

}