How does Magento 2 iterate through the backend config form fields?

dmitry_fedyuk · November 14, 2015, 4:48pm

Magento 2 uses Flyweight design pattern for iterating through the config fields:

magento/magento2/blob/2335247d4ae2dc1e0728ee73022b0a244ccd7f4c/app/code/Magento/Config/Model/Config/Structure/Element/Iterator/Field.php#L28-L34


public function __construct(
    \Magento\Config\Model\Config\Structure\Element\Group $groupFlyweight,
    \Magento\Config\Model\Config\Structure\Element\Field $fieldFlyweight
) {
    $this->_groupFlyweight = $groupFlyweight;
    $this->_fieldFlyweight = $fieldFlyweight;
}

github.com

magento/magento2/blob/2335247d4ae2dc1e0728ee73022b0a244ccd7f4c/app/code/Magento/Config/Model/Config/Structure/Element/Group.php#L36


/**
 * @param \Magento\Store\Model\StoreManagerInterface $storeManager
 * @param \Magento\Framework\Module\Manager $moduleManager
 * @param Iterator\Field $childrenIterator
 * @param \Magento\Config\Model\Config\BackendClone\Factory $cloneModelFactory
 * @param Dependency\Mapper $dependencyMapper
 */
public function __construct(
    \Magento\Store\Model\StoreManagerInterface $storeManager,
    \Magento\Framework\Module\Manager $moduleManager,
    \Magento\Config\Model\Config\Structure\Element\Iterator\Field $childrenIterator,
    \Magento\Config\Model\Config\BackendClone\Factory $cloneModelFactory,
    \Magento\Config\Model\Config\Structure\Element\Dependency\Mapper $dependencyMapper
) {
    parent::__construct($storeManager, $moduleManager, $childrenIterator);
    $this->_cloneModelFactory = $cloneModelFactory;
    $this->_dependencyMapper = $dependencyMapper;
}


/**
 * Should group fields be cloned

github.com

magento/magento2/blob/2335247d4ae2dc1e0728ee73022b0a244ccd7f4c/app/code/Magento/Config/Model/Config/Structure/Element/Iterator.php#L68-L71


public function current()
{
    return $this->_flyweight;
}

github.com

magento/magento2/blob/2335247d4ae2dc1e0728ee73022b0a244ccd7f4c/app/code/Magento/Config/Model/Config/Structure/Element/Iterator.php#L78-L87


public function next()
{
    next($this->_elements);
    if (current($this->_elements)) {
        $this->_initFlyweight(current($this->_elements));
        if (!$this->current()->isVisible()) {
            $this->next();
        }
    }
}

github.com

magento/magento2/blob/2335247d4ae2dc1e0728ee73022b0a244ccd7f4c/app/code/Magento/Config/Model/Config/Structure/Element/AbstractComposite.php#L68-L71


public function getChildren()
{
    return $this->_childrenIterator;
}

github.com

magento/magento2/blob/2335247d4ae2dc1e0728ee73022b0a244ccd7f4c/app/code/Magento/Config/Block/System/Config/Form.php#L268


    $labelPrefix = ''
) {
    if (!$this->_configDataObject) {
        $this->_initObjects();
    }


    // Extends for config data
    $extraConfigGroups = [];


    /** @var $element \Magento\Config\Model\Config\Structure\Element\Field */
    foreach ($group->getChildren() as $element) {
        if ($element instanceof \Magento\Config\Model\Config\Structure\Element\Group) {
            $this->_initGroup($element, $section, $fieldset);
        } else {
            $path = $element->getConfigPath() ?: $element->getPath($fieldPrefix);
            if ($element->getSectionId() != $section->getId()) {
                $groupPath = $element->getGroupPath();
                if (!isset($extraConfigGroups[$groupPath])) {
                    $this->_configData = $this->_configDataObject->extendConfig(
                        $groupPath,
                        false,

dmitry_fedyuk · November 14, 2015, 4:50pm

See also How does Magento 2 prepare a backend config form field for rendering?

dmitry_fedyuk · November 17, 2015, 6:59am