public class Main { public static void main(String[] args) { // creates an ordinary list List<Integer> list = new ArrayList<>(); // to make the list observable, we wrap it in a VList VList<Integer> vList = VList.newInstance(list); // to get notified, we add a change listener to the VList Subscription subscription = vList.addChangeListener((evt) -> { // for now, we just print the changes System.out.println(EventUtil.toStringWithDetails(evt)); }); // add individual elements (generates 3 events) System.out.println(">> add 3 individual elements"); vList.add(1); vList.add(2); vList.add(3); // add collection of elements (generates only one event) System.out.println(">> add one collection of elements"); vList.addAll(Arrays.asList(4, 5, 6)); // remove individual elements (generates 3 events) System.out.println(">> remove 3 individual elements"); vList.remove((Integer) 1); vList.remove((Integer) 2); vList.remove((Integer) 3); // remove collection of elements (generates only one event) System.out.println(">> remove one collection of elements"); vList.removeAll(Arrays.asList(4,5,6)); // unsubscribe the listener from vList subscription.unsubscribe();        // add elements without generating events System.out.println(">> add one collection of elements without notification"); vList.addAll(Arrays.asList(4, 5, 6)); } }

public class Main { public static void main(String[] args) { // creates an ordinary list List<Integer> list = new ArrayList<>(); // to make the list observable, we wrap it in a VList VList<Integer> vList = VList.newInstance(list); // How to make the list unmodifiable and still listen to changes? // THIS DOES NOT WORK: VList.newInstance(Collections.unmodifiableList(list)); VList<Integer> vListUnmodifiable = vList.asUnmodifiable(); // to get notified, we add a change listener to the unmodifiable VList Subscription subscription = vListUnmodifiable.addChangeListener((evt) -> { // for now, we just print the changes System.out.println(EventUtil.toStringWithDetails(evt)); }); // add element and generate event vList.add(1); // modifying the unmodifiable list results in RuntimeException... vListUnmodifiable.add(37); } }