public void bind(ButtonHandler handler) {
/* Calculate the hash for the widget */
int hash = Widget.getHash(handler.getParent(), handler.getChild());
List<ButtonHandler> list = handlerLists.get(hash);
/* Create and store the list if it does not exist */
if (list == null) {
list = new LinkedList<>();
handlerLists.put(hash, list);
}
/* Add the handler to the list */
list.add(handler);
}
