public void broadcastChanges() {
    for (PageChangeSubscriber sub : subscribers) {
      sub.addChanges((PageChanges) changes.clone());
    }

    changes = new PageChanges();
  }
 public void addNewEntityChanges(Collection<AddRemEntChange> changesToAdd) {
   changes.addNewEntityChanges(changesToAdd);
 }
 public void addEntityChanges(Collection<EntityChange> changesToAdd) {
   changes.addEntityChanges(changesToAdd);
 }
 public void addBoardChanges(Collection<BoardChange> changesToAdd) {
   changes.addBoardChanges(changesToAdd);
 }