class MenuLinkTreeElement in Drupal 9

Provides a value object to model an element in a menu link tree.

\Drupal\Core\Menu\MenuLinkTreeElement objects represent a menu link's data. Objects of this class provide complimentary data: the placement in a tree. Therefore, we can summarize this split as follows:

• Menu link objects contain all information about an individual menu link, plus what their parent is. But they don't know where exactly in a menu link tree they live.
• Instances of this class are complimentary to those objects, they know:
  • All additional metadata from {menu_tree}, which contains "materialized" metadata about a menu link tree, such as whether a link in the tree has visible children and the depth relative to the root.
  • Plus all additional metadata that's adjusted for the current tree query, such as whether the link is in the active trail, whether the link is accessible for the current user, and the link's children (which are only loaded if the link was marked as "expanded" by the query).

Hierarchy

• class \Drupal\Core\Menu\MenuLinkTreeElement

See also

\Drupal\Core\Menu\MenuTreeStorage::loadTreeData()

4 files declare their use of MenuLinkTreeElement

MenuForm.php in core/modules/menu_ui/src/MenuForm.php

MenuLinkTreeElementTest.php in core/tests/Drupal/Tests/Core/Menu/MenuLinkTreeElementTest.php

MenuLinkTreeTest.php in core/tests/Drupal/KernelTests/Core/Menu/MenuLinkTreeTest.php

MenuLinkTreeTest.php in core/modules/system/tests/src/Unit/Menu/MenuLinkTreeTest.php

File

core/lib/Drupal/Core/Menu/MenuLinkTreeElement.php, line 25

Namespace

Drupal\Core\Menu

class MenuLinkTreeElement {

  /**
   * The menu link for this element in a menu link tree.
   *
   * @var \Drupal\Core\Menu\MenuLinkInterface
   */
  public $link;

  /**
   * The subtree of this element in the menu link tree (this link's children).
   *
   * (Children of a link are only loaded if a link is marked as "expanded" by
   * the query.)
   *
   * @var \Drupal\Core\Menu\MenuLinkTreeElement[]
   */
  public $subtree;

  /**
   * The depth of this link relative to the root of the tree.
   *
   * @var int
   */
  public $depth;

  /**
   * Whether this link has any children at all.
   *
   * @var bool
   */
  public $hasChildren;

  /**
   * Whether this link is in the active trail.
   *
   * @var bool
   */
  public $inActiveTrail;

  /**
   * Whether this link is accessible by the current user.
   *
   * If the value is NULL the access was not determined yet, if an access result
   * object, it was determined already.
   *
   * @var \Drupal\Core\Access\AccessResultInterface|null
   */
  public $access;

  /**
   * Additional options for this link.
   *
   * This is merged (\Drupal\Component\Utility\NestedArray::mergeDeep()) with
   * \Drupal\Core\Menu\MenuLinkInterface::getOptions(), to allow menu link tree
   * manipulators to add or override link options.
   */
  public $options = [];

  /**
   * Constructs a new \Drupal\Core\Menu\MenuLinkTreeElement.
   *
   * @param \Drupal\Core\Menu\MenuLinkInterface $link
   *   The menu link for this element in the menu link tree.
   * @param bool $has_children
   *   A flag as to whether this element has children even if they are not
   *   included in the tree (i.e. this may be TRUE even if $subtree is empty).
   * @param int $depth
   *   The depth of this element relative to the tree root.
   * @param bool $in_active_trail
   *   A flag as to whether this link was included in the list of active trail
   *   IDs used to build the tree.
   * @param \Drupal\Core\Menu\MenuLinkTreeElement[] $subtree
   *   The children of this element in the menu link tree.
   */
  public function __construct(MenuLinkInterface $link, $has_children, $depth, $in_active_trail, array $subtree) {

    // Essential properties.
    $this->link = $link;
    $this->hasChildren = $has_children;
    $this->depth = $depth;
    $this->subtree = $subtree;
    $this->inActiveTrail = $in_active_trail;
  }

  /**
   * Counts all menu links in the current subtree.
   *
   * @return int
   *   The number of menu links in this subtree (one plus the number of menu
   *   links in all descendants).
   */
  public function count() {
    $sum = function ($carry, MenuLinkTreeElement $element) {
      return $carry + $element
        ->count();
    };
    return 1 + array_reduce($this->subtree, $sum);
  }

}

Members

Name	Modifiers	Type	Description	Overrides
MenuLinkTreeElement::$access	public	property	Whether this link is accessible by the current user.
MenuLinkTreeElement::$depth	public	property	The depth of this link relative to the root of the tree.
MenuLinkTreeElement::$hasChildren	public	property	Whether this link has any children at all.
MenuLinkTreeElement::$inActiveTrail	public	property	Whether this link is in the active trail.
MenuLinkTreeElement::$link	public	property	The menu link for this element in a menu link tree.
MenuLinkTreeElement::$options	public	property	Additional options for this link.
MenuLinkTreeElement::$subtree	public	property	The subtree of this element in the menu link tree (this link's children).
MenuLinkTreeElement::count	public	function	Counts all menu links in the current subtree.
MenuLinkTreeElement::__construct	public	function	Constructs a new \Drupal\Core\Menu\MenuLinkTreeElement.