public class X {
    @TemplateRegistration(
        page = "cz/xelfi/test/x.html",
        scriptEngine = "freemarker",
        displayName = "JS Wizard",
        folder = "Other",
        content = "x.fmk"
    )
    public static String jsWizard() {
        return "init();";
    }
}

   function init() {
        var ok = ko.observable(false);
        var msg = ko.observable('');
        var current = ko.observable('Init');
        var data = {
            'errorCode': ko.computed(function() {
                if ('Init' == current()) return 0;
                if (!ok()) return 1;
                if (msg()) return 0;
                return 2;
            }),
            'steps': ko.observableArray([ 'Init', 'Info', 'Summary']),
            'current': current,
            'ok': ok,
            'msg' : msg
        }
        return data;
    }

<script type="text/html" id="Init">
    <h1>This is Initial Page</h1>
    <p>
        JavaScript will ask you few questions about your mood.
    </p>
</script>

<script type="text/html" id="Info">
    <h1>This is Query Page</h1>
    <p>
    Is everything OK?
    </p>
    <input type="checkbox" data-bind="checked: ok"/>
    <p>How do you feel?
    </p>
    <input type='text' data-bind="value: msg"/>
</script>

<script type="text/html" id="Summary">
    <h1>This is Summary Page</h1>
    <p>
        You are feeling <span data-bind="text: msg"></span>!
    </p>
</script>

<div data-bind="visible: errorCode() == 1">
    <span style="color: red">Please check you are OK!</span>
</div>

<div data-bind="visible: errorCode() == 2">
    <span style="color: red">Tell us how do you feel!</span>
</div>

Hi,
I am Freemarker.
I feel ${wizard.msg}.

@Model(className = "Y", properties = {
    @Property(name = "steps", type = String.class, array = true),
    @Property(name = "current", type = String.class),
    @Property(name = "ok", type = boolean.class),
    @Property(name = "msg", type = String.class)
})
public class YCntrl {
    @ComputedProperty static int errorCode(
        String current, boolean ok, String msg
    ) {
        if ("Init".equals(current)) return 0;
        if (!ok) return 1;
        if (msg == null || msg.isEmpty()) return 2;
        return 0;
    }


    @TemplateRegistration(
        page = "cz/xelfi/test/x.html",
        scriptEngine = "freemarker",
        displayName = "HTML/Java Wizard",
        folder = "Java",
        content = "x.fmk"
    )
    public static Y jsWizard() {
        return new Y("Init", false, "",
          "Init", "Info", "Summary"
        );
    }
}