private void notifyChanged() {
        for (List<Consumer<PersistableFolder>> list : this.changeListeners.values()) {
            for (Consumer<PersistableFolder> listener : list) {
                listener.accept(this);
            }
        }
    }
registers a listener which is fired each time the actual location of this folder changes
main/src/main/java/cgeo/geocaching/storage/PersistableFolder.java