Question

Is there any standard approach to input data validation and error displaying in GWT+GAE-based application?

Eclipse plugin generates GWT project with shared.FieldVerifier class, which provides static method for values validation:

public static boolean isValidName(String name) {
    if (name == null) {
        return false;
    }
    return name.length() > 3;
}

isValidName() method is then called on input data in client-side code and server-side code, and if something is wrong, error logics is executed. BTW, I suppose, this approach (set of static validation methods, specific error displaying logics in each case) may be not very scalable.

Also, I found gwt-validation project on code.google.com, but I did not investigate it yet.

Could you please recommend any standard approaches / libraries, which can help to handle validation and error displaying? Is gwt-validation library a standard?

Answer 1

The standard is JSR303 and can be used to validate client side as well on the server side.

Please have a look at this topic:
GWT JSR 303 client validation