storage

 public class AttributeSetup<T> { // better name ?

        private final T defaultValue;
        private T actualValue;

        public AttributeSetup(T defaultValue) {
            if (defaultValue == null) {
                throw new IllegalArgumentException("Default value cannot be null!");
            }
            this.defaultValue = defaultValue;
            this.actualValue = defaultValue;
        }

        public T getValue() {
            return actualValue;
        }

        public void resetValue() {
            actualValue = defaultValue;
        }

        public void setValue(T value) {
            if (value == null) {
                throw new IllegalArgumentException("Cannot set value to null!");
            }
            actualValue = value;
        }

        public static <T> AttributeSetup<T> createAttributeSetup(T defaultValue) {
            return new AttributeSetup<T>(defaultValue);
        }
}

// with previous value ?
public class AttributeSetupWithPreviousValue<T> extends Storage<T> {
   public void setToPreviousValue();
}

========================
Use
========================

Transform this:
        private static final Event DEFAULT_EVENT = Event.CLICK;
        private Event toggleEvent = DEFAULT_EVENT;

        public Event getToggleEvent() {
            return toggleEvent;
        }

        public void setupToggleEvent() {
            toggleEvent = DEFAULT_EVENT;
        }

        public void setupToggleEvent(Event e) {
            toggleEvent = e;
        }

fragment.advanced().setupToggleEvent(event);
fragment.advanced().setupToggleEvent();
fragment.advanced().getToggleEvent();

To this:

    private final AttributeSetup<Event> toggleEvent = AttributeSetup.createAttributeSetup(Event.CLICK);

    public AttributeSetup<Event> toggleEvent() {// better name?
        return toggleEvent;
    }

fragment.advanced().toggleEvent().setValue(event);
fragment.advanced().toggleEvent().resetValue();
fragment.advanced().toggleEvent().getValue();