code: public TemplateClass getTemplateClass(ITemplateResource resource) {
          String key = S.str(resource.getKey());
          TemplateClass tc = classes().getByTemplate(key);
          if (null == tc) {
              tc = new TemplateClass(resource, this);
          }
          return tc;
      }
docs: (3rd party API, not for user application)
  Get an new template class by {@link org.rythmengine.resource.ITemplateResource template resource}
  
  @param resource the template resource
  @return template class