EntityHandlerBase.php

<?php

namespace Drupal\Core\Entity;

use Drupal\Core\DependencyInjection\DependencySerializationTrait;
use Drupal\Core\Extension\ModuleHandlerInterface;
use Drupal\Core\StringTranslation\StringTranslationTrait;

/**
 * Provides a base class for entity handlers.
 *
 * @ingroup entity_api
 */
abstract class EntityHandlerBase {
    use StringTranslationTrait;
    use DependencySerializationTrait;
    
    /**
     * The module handler to invoke hooks on.
     *
     * @var \Drupal\Core\Extension\ModuleHandlerInterface
     */
    protected $moduleHandler;
    
    /**
     * Gets the module handler.
     *
     * @return \Drupal\Core\Extension\ModuleHandlerInterface
     *   The module handler.
     */
    protected function moduleHandler() {
        if (!$this->moduleHandler) {
            $this->moduleHandler = \Drupal::moduleHandler();
        }
        return $this->moduleHandler;
    }
    
    /**
     * Sets the module handler for this handler.
     *
     * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
     *   The module handler.
     *
     * @return $this
     */
    public function setModuleHandler(ModuleHandlerInterface $module_handler) {
        $this->moduleHandler = $module_handler;
        return $this;
    }

}