Vaadin JavaScript server-side component

VueComponent.java

@StyleSheet({"colorPicker.css"})
@JavaScript({"vue.js","es6-promise.auto.js", "vuex.js", "bundle.js", "vaadin-injector.js"})
public class VueComponent extends AbstractJavaScriptComponent {

    private Consumer<Color> onColorChangedConsumer;

    public VueComponent() {
        setId("app");
        addFunction("onSyncColorPicker", arguments -> {
            Notification.show("Message from VUE: " + arguments.get(0).asString());

            if (onColorChangedConsumer != null) {
                int r = (int)arguments.getObject(0).getObject("rgba").getNumber("r");
                int g = (int)arguments.getObject(0).getObject("rgba").getNumber("g");
                int b = (int)arguments.getObject(0).getObject("rgba").getNumber("b");
                int a = (int)arguments.getObject(0).getObject("rgba").getNumber("a");
                Notification.show("Color Changed to r:" + r + ", g:" + g + ", b:" + b + ", a:" + a);
                onColorChangedConsumer.accept(new Color(r, g, b, a));
            }
        });
    }

    public void onColorChanged(Consumer<Color> onColorChangedConsumer) {
        this.onColorChangedConsumer = onColorChangedConsumer;
    }

    @Override
    public VueState getState() {
        return (VueState)super.getState();
    }
}