code: private void setField(Field field, Object object, Class<?> type)
      {
          try
          {
              if (field.get(object) == null)
              {
                  final Class<? extends Feature> clazz;
                  // CHECKSTYLE IGNORE LINE: InnerAssignment
                  if (Feature.class.isAssignableFrom(type) && hasFeature(clazz = type.asSubclass(Feature.class)))
                  {
                      field.set(object, getFeature(clazz));
                  }
                  else if (media != null)
                  {
                      throw new LionEngineException(media, ERROR_CLASS_PRESENCE + String.valueOf(type) + IN + object);
                  }
                  else
                  {
                      throw new LionEngineException(ERROR_CLASS_PRESENCE + String.valueOf(type) + IN + object);
                  }
              }
          }
          catch (final IllegalAccessException exception)
          {
              throw new LionEngineException(exception,
                                            ERROR_INJECT + type.getSimpleName() + Constant.SLASH + field.getName());
          }
      }
docs: Set the field service only if currently <code>null</code>.
  
  @param field The field to set.
  @param object The object to update.
  @param type The service type.
  @throws LionEngineException If error on setting service.