NumberCaptcha Add-on

A simple CAPTCHA component that asks users to key in a few digits to prove they are human.

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This component is merely a skeleton component to show the minimum needed for a widget that is implemented in JavaScript (not GWT). It uses a shared state (provided to the JavaScript end internally using the GWT compiler) that updates the client when it changes (programmatically from the server side) and a call-back mechanism from client to server.

Sample code

VerticalLayout content = new VerticalLayout();
        setContent(content);

        content.addComponent(new NumberCaptcha(4, 3000, "Pos %d, enter %s as a digit", "Hit RETURN to continue when finished.") {
            @Override
            public void captchaGood() {
                Notification.show("Good, you are a human being. Thanks.");
            }

            @Override
            public void captchaBad() {
                Notification.show("Please try again.");
            }
        });

Links

• Author Homepage
• Source Code

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