Spring Boot Form Validation with JTE about jte HOT 4 CLOSED

public class JteContext {
    public static class ctx {
        public static class form {

            private static final ThreadLocal<BindingResult> bindingResultContext = new ThreadLocal<>();

            public static void init(BindingResult bindingResult) {
                bindingResultContext.set(bindingResult);
            }

            public static boolean hasFieldError(String fieldName) {
                return bindingResultContext.get() != null && bindingResultContext.get().hasFieldErrors(fieldName);
            }

            public static boolean hasGlobalError() {
                return bindingResultContext.get() != null && bindingResultContext.get().hasGlobalErrors();
            }

            public static String getFieldError(String fieldName) {
                if (bindingResultContext.get() == null) {
                    return "";
                }

                FieldError fieldError = bindingResultContext.get().getFieldError(fieldName);

                return Optional.ofNullable(fieldError)
                        .map(fe -> i18n.localizerContext.get()
                                .getMessageSource()
                                .getMessage(fe, LocaleContextHolder.getLocale())
                        )
                        .orElse("");
            }

            public static String getGlobalError() {
                BindingResult bindingResult = bindingResultContext.get();
                if (bindingResult == null) {
                    return "";
                }

                if (!bindingResult.hasGlobalErrors()) {
                    return "";
                }

                return bindingResult.getGlobalErrors().iterator().next().getDefaultMessage();
            }
        }
    }
}

@RequiredArgsConstructor
public class JteContextInterceptor implements HandlerInterceptor {

    private final MessageSource messageSource;

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {
        JteContext.ctx.i18n.init(new JteLocalizer(this.messageSource, LocaleContextHolder.getLocale()));
        JteContext.ctx.request.init(request);
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) {
        if (modelAndView == null) {
            return;
        }

        // in order to be able to access the form's BindingResult we need to intercept it here and initialize it in
        // the JteContext as a ThreadLocal.
        // the alternative would be to declare it as a param on the relevant .jte file, but seeing as that would be a form, it would then
        // have to pass the BindingResult as a param to each input on the form, this leads to a cascade of passing the BindingResult along
        // the approach used here to set it in a ThreadLocal which can then be accessed directly at the correct level seems easier and cleaner
        Map<String, Object> model = modelAndView.getModel();
        if (model.containsKey("org.springframework.validation.BindingResult.form")) {
            BindingResult bindingResult = (BindingResult) model.get("org.springframework.validation.BindingResult.form");
            JteContext.ctx.form.init(bindingResult);
        }
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) {
        JteContext.dispose();
    }
}

@import static be.bluemagma.web.infrastructure.jte.JteContext.*

<input  class="input ${ctx.form.hasFieldError("firstName") ? "is-danger" : ""}">

@if(ctx.form.hasFieldError("firstName"))
    <p class="help is-danger">
        ${ctx.form.getFieldError("firstName")}
    </p>
@endif