ConditionManager.php

<?php

namespace Drupal\Core\Condition;

use Drupal\Component\Plugin\CategorizingPluginManagerInterface;
use Drupal\Core\Cache\CacheBackendInterface;
use Drupal\Core\Executable\ExecutableException;
use Drupal\Core\Executable\ExecutableManagerInterface;
use Drupal\Core\Executable\ExecutableInterface;
use Drupal\Core\Extension\ModuleHandlerInterface;
use Drupal\Core\Plugin\CategorizingPluginManagerTrait;
use Drupal\Core\Plugin\DefaultPluginManager;
use Drupal\Core\Plugin\FilteredPluginManagerInterface;
use Drupal\Core\Plugin\FilteredPluginManagerTrait;

/**
 * A plugin manager for condition plugins.
 *
 * @see \Drupal\Core\Condition\Annotation\Condition
 * @see \Drupal\Core\Condition\ConditionInterface
 * @see \Drupal\Core\Condition\ConditionPluginBase
 *
 * @ingroup plugin_api
 */
class ConditionManager extends DefaultPluginManager implements ExecutableManagerInterface, CategorizingPluginManagerInterface, FilteredPluginManagerInterface {
    use CategorizingPluginManagerTrait;
    use FilteredPluginManagerTrait;
    
    /**
     * Constructs a ConditionManager object.
     *
     * @param \Traversable $namespaces
     *   An object that implements \Traversable which contains the root paths
     *   keyed by the corresponding namespace to look for plugin implementations.
     * @param \Drupal\Core\Cache\CacheBackendInterface $cache_backend
     *   Cache backend instance to use.
     * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
     *   The module handler to invoke the alter hook with.
     */
    public function __construct(\Traversable $namespaces, CacheBackendInterface $cache_backend, ModuleHandlerInterface $module_handler) {
        $this->alterInfo('condition_info');
        $this->setCacheBackend($cache_backend, 'condition_plugins');
        parent::__construct('Plugin/Condition', $namespaces, $module_handler, 'Drupal\\Core\\Condition\\ConditionInterface', 'Drupal\\Core\\Condition\\Annotation\\Condition');
    }
    
    /**
     * {@inheritdoc}
     */
    protected function getType() {
        return 'condition';
    }
    
    /**
     * {@inheritdoc}
     */
    public function createInstance($plugin_id, array $configuration = []) {
        $plugin = $this->getFactory()
            ->createInstance($plugin_id, $configuration);
        // If we receive any context values via config set it into the plugin.
        if (!empty($configuration['context'])) {
            foreach ($configuration['context'] as $name => $context) {
                $plugin->setContextValue($name, $context);
            }
        }
        return $plugin->setExecutableManager($this);
    }
    
    /**
     * {@inheritdoc}
     */
    public function execute(ExecutableInterface $condition) {
        if ($condition instanceof ConditionInterface) {
            $result = $condition->evaluate();
            return $condition->isNegated() ? !$result : $result;
        }
        throw new ExecutableException("This manager object can only execute condition plugins");
    }

}