CheckParams.java

public interface RouteDSL {
  
  RouteDSL param(String paramName, Handler<RoutingContext> checker)
   
  default<T> RouteDSL param(String paramName, Function<String, T> checker) {
    return param(paramName, ctx -> {
      String p = ctx.request().getParam(name);
      try {
        ctx.put(paramName, checker.apply(p));
        ctx.next();
      } catch(Exception e) {
        ctx.response().setStatusCode(400).end("Invalid parameter " + name);
      }
    };
  }
                 
  RouteDSL param(String paramName, Handler<RoutingContext> checker)
   
  default<T> RouteDSL asyncParam(String paramName, Function<String, Future<T>> checker) {
    return param(paramName, ctx -> {
      String p = ctx.request().getParam(name);
      checker.apply(p).setHandler(res -> {
        if (res.failed()) {
          ctx.fail(res.cause());
        } else {
          ctx.put(paramName, res.result());
          ctx.next();
        }
    };
  }

                 
}