trait StringTranslationTrait

trait StringTranslationTrait {
    
    /**
     * The string translation service.
     *
     * @var \Drupal\Core\StringTranslation\TranslationInterface
     */
    protected $stringTranslation;
    
    /**
     * Translates a string to the current language or to a given language.
     *
     * See \Drupal\Core\StringTranslation\TranslatableMarkup::__construct() for
     * important security information and usage guidelines.
     *
     * In order for strings to be localized, make them available in one of the
     * ways supported by the
     * @link https://www.drupal.org/node/322729 Localization API @endlink. When
     * possible, use the \Drupal\Core\StringTranslation\StringTranslationTrait
     * $this->t(). Otherwise create a new
     * \Drupal\Core\StringTranslation\TranslatableMarkup object.
     *
     * @param string $string
     *   A string containing the English text to translate.
     * @param array $args
     *   (optional) An associative array of replacements to make after
     *   translation. Based on the first character of the key, the value is
     *   escaped and/or themed. See
     *   \Drupal\Component\Render\FormattableMarkup::placeholderFormat() for
     *   details.
     * @param array $options
     *   (optional) An associative array of additional options, with the following
     *   elements:
     *   - 'langcode' (defaults to the current language): A language code, to
     *     translate to a language other than what is used to display the page.
     *   - 'context' (defaults to the empty context): The context the source
     *     string belongs to. See the
     *     @link i18n Internationalization topic @endlink for more information
     *     about string contexts.
     *
     * @return \Drupal\Core\StringTranslation\TranslatableMarkup
     *   An object that, when cast to a string, returns the translated string.
     *
     * @see \Drupal\Component\Render\FormattableMarkup::placeholderFormat()
     * @see \Drupal\Core\StringTranslation\TranslatableMarkup::__construct()
     *
     * @ingroup sanitization
     */
    protected function t($string, array $args = [], array $options = []) {
        return new TranslatableMarkup($string, $args, $options, $this->getStringTranslation());
    }
    
    /**
     * Formats a string containing a count of items.
     *
     * @see \Drupal\Core\StringTranslation\TranslationInterface::formatPlural()
     *
     * @return \Drupal\Core\StringTranslation\PluralTranslatableMarkup
     *   An object that, when cast to a string, returns the translated string.
     */
    protected function formatPlural($count, $singular, $plural, array $args = [], array $options = []) {
        return new PluralTranslatableMarkup($count, $singular, $plural, $args, $options, $this->getStringTranslation());
    }
    
    /**
     * Returns the number of plurals supported by a given language.
     *
     * @see \Drupal\locale\PluralFormulaInterface::getNumberOfPlurals()
     *
     * @return int
     *   The number of plurals supported.
     */
    protected function getNumberOfPlurals($langcode = NULL) {
        if (\Drupal::hasService('locale.plural.formula')) {
            return \Drupal::service('locale.plural.formula')->getNumberOfPlurals($langcode);
        }
        // We assume 2 plurals if Locale's services are not available.
        return 2;
    }
    
    /**
     * Gets the string translation service.
     *
     * @return \Drupal\Core\StringTranslation\TranslationInterface
     *   The string translation service.
     */
    protected function getStringTranslation() {
        if (!$this->stringTranslation) {
            $this->stringTranslation = \Drupal::service('string_translation');
        }
        return $this->stringTranslation;
    }
    
    /**
     * Sets the string translation service to use.
     *
     * @param \Drupal\Core\StringTranslation\TranslationInterface $translation
     *   The string translation service.
     *
     * @return $this
     */
    public function setStringTranslation(TranslationInterface $translation) {
        $this->stringTranslation = $translation;
        return $this;
    }

}