interface ContentEntityFormInterface

interface ContentEntityFormInterface extends EntityFormInterface {
    
    /**
     * Gets the form display.
     *
     * @param \Drupal\Core\Form\FormStateInterface $form_state
     *   The current state of the form.
     *
     * @return \Drupal\Core\Entity\Display\EntityFormDisplayInterface
     *   The current form display.
     */
    public function getFormDisplay(FormStateInterface $form_state);
    
    /**
     * Sets the form display.
     *
     * Sets the form display which will be used for populating form element
     * defaults.
     *
     * @param \Drupal\Core\Entity\Display\EntityFormDisplayInterface $form_display
     *   The form display that the current form operates with.
     * @param \Drupal\Core\Form\FormStateInterface $form_state
     *   The current state of the form.
     *
     * @return $this
     */
    public function setFormDisplay(EntityFormDisplayInterface $form_display, FormStateInterface $form_state);
    
    /**
     * Gets the code identifying the active form language.
     *
     * @param \Drupal\Core\Form\FormStateInterface $form_state
     *   The current state of the form.
     *
     * @return string
     *   The form language code.
     */
    public function getFormLangcode(FormStateInterface $form_state);
    
    /**
     * Checks whether the current form language matches the entity one.
     *
     * @param \Drupal\Core\Form\FormStateInterface $form_state
     *   The current state of the form.
     *
     * @return bool
     *   Returns TRUE if the entity form language matches the entity one.
     */
    public function isDefaultFormLangcode(FormStateInterface $form_state);
    
    /**
     * {@inheritdoc}
     *
     * Note that extending classes should not override this method to add entity
     * validation logic, but define further validation constraints using the
     * entity validation API and/or provide a new validation constraint if
     * necessary. This is the only way to ensure that the validation logic
     * is correctly applied independently of form submissions; e.g., for REST
     * requests.
     * For more information about entity validation, see
     * https://www.drupal.org/node/2015613.
     *
     * @return \Drupal\Core\Entity\ContentEntityInterface
     *   The built entity.
     */
    public function validateForm(array &$form, FormStateInterface $form_state);

}