BeanValidationBinder reports valid even though using validation API directly reports invalid #9453
Description
Vaadin 8
Repeatable with following example code:
public class MyUI extends UI {
public static class Entity {
@NotNull
//@Size(min = 3, max = 10)
private String name;
public void setName(String name) {
this.name = name;
}
public String getName() {
return name;
}
@Override
public String toString() {
return "Entity, name: " + name;
}
}
final TextField name = new TextField();
@Override
protected void init(VaadinRequest vaadinRequest) {
final VerticalLayout layout = new VerticalLayout();
name.setCaption("Type your name here:");
Entity entity = new Entity();
Binder<Entity> b = new BeanValidationBinder<>(Entity.class);
//b.forMemberField(name).withNullRepresentation(""); // This seems to fix the issue
b.bindInstanceFields(this);
b.setBean(entity);
Button button = new Button("Check validity");
button.addClickListener(e -> {
ValidatorFactory factory = Validation.buildDefaultValidatorFactory();
Validator validator = factory.getValidator();
Set<ConstraintViolation<Entity>> validate = validator.validate(entity);
String msg = String.format("Binder.isValid: %s, JSR 303 valid: %s, name: %s", b.isValid(), validate.isEmpty(), entity.getName());
Notification.show(msg);
});
layout.addComponents(name);
layout.addComponent(button);
setContent(layout);
}
@WebServlet(urlPatterns = "/*", name = "MyUIServlet", asyncSupported = true)
@VaadinServletConfiguration(ui = MyUI.class, productionMode = false)
public static class MyUIServlet extends VaadinServlet {
}
}
It took me long to realise what was wrong, but BeanValidationBinder seems to do the validation over the field value instead of the actual bean state, even though "non-buffered mode" (setBean method) is used. This "functionality" makes odd situations when invalid stuff from UI is passed to the backend and the UI developer would expect that it could never happen.