trait CategorizingPluginManagerTrait

trait CategorizingPluginManagerTrait {
    use StringTranslationTrait;
    
    /**
     * Processes a plugin definition to ensure there is a category.
     *
     * If the definition lacks a category, it defaults to the providing module.
     *
     * @param array $definition
     *   The plugin definition.
     */
    protected function processDefinitionCategory(&$definition) {
        // Ensure that every plugin has a category.
        if (empty($definition['category'])) {
            // Default to the human readable module name if the provider is a module;
            // otherwise the provider machine name is used.
            $definition['category'] = $this->getProviderName($definition['provider']);
        }
    }
    
    /**
     * Gets the name of a provider.
     *
     * @param string $provider
     *   The machine name of a plugin provider.
     *
     * @return string
     *   The human-readable module name if it exists, otherwise the
     *   machine-readable name passed.
     */
    protected function getProviderName($provider) {
        $list = $this->getModuleHandler()
            ->getModuleList();
        // If the module exists, return its human-readable name.
        if (isset($list[$provider])) {
            return $this->getModuleHandler()
                ->getName($provider);
        }
        // Otherwise, return the machine name.
        return $provider;
    }
    
    /**
     * Returns the module handler used.
     *
     * @return \Drupal\Core\Extension\ModuleHandlerInterface
     *   The module handler.
     */
    public function getModuleHandler() {
        // If the class has an injected module handler, use it. Otherwise fall back
        // to fetch it from the service container.
        if (isset($this->moduleHandler)) {
            return $this->moduleHandler;
        }
        return \Drupal::moduleHandler();
    }
    
    /**
     * {@inheritdoc}
     */
    public function getCategories() {
        
        /** @var \Drupal\Core\Plugin\CategorizingPluginManagerTrait|\Drupal\Component\Plugin\PluginManagerInterface $this */
        // Fetch all categories from definitions and remove duplicates.
        $categories = array_unique(array_values(array_map(function ($definition) {
            return $definition['category'];
        }, $this->getDefinitions())));
        natcasesort($categories);
        return $categories;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getSortedDefinitions(array $definitions = NULL, $label_key = 'label') {
        // Sort the plugins first by category, then by label.
        
        /** @var \Drupal\Core\Plugin\CategorizingPluginManagerTrait|\Drupal\Component\Plugin\PluginManagerInterface $this */
        $definitions = isset($definitions) ? $definitions : $this->getDefinitions();
        uasort($definitions, function ($a, $b) use ($label_key) {
            if ($a['category'] != $b['category']) {
                return strnatcasecmp($a['category'], $b['category']);
            }
            return strnatcasecmp($a[$label_key], $b[$label_key]);
        });
        return $definitions;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getGroupedDefinitions(array $definitions = NULL, $label_key = 'label') {
        
        /** @var \Drupal\Core\Plugin\CategorizingPluginManagerTrait|\Drupal\Component\Plugin\PluginManagerInterface $this */
        $definitions = $this->getSortedDefinitions(isset($definitions) ? $definitions : $this->getDefinitions(), $label_key);
        $grouped_definitions = [];
        foreach ($definitions as $id => $definition) {
            $grouped_definitions[(string) $definition['category']][$id] = $definition;
        }
        return $grouped_definitions;
    }

}