public class ObservationOperationHistoryListener implements IOperationHistoryListener
{
    public void historyNotification(OperationHistoryEvent event)
    {
        IUndoableOperation op = event.getOperation();
        if (op instanceof TriggeredOperations)
            op = ((TriggeredOperations) op).getTriggeringOperation();
        UndoableOperation2ChangeAdapter changeOperation = null;
        if (op instanceof UndoableOperation2ChangeAdapter)
            changeOperation = (UndoableOperation2ChangeAdapter) op;
        if (changeOperation == null)
            return;
        Change change = changeOperation.getChange();
        if (change == null)
            return;
        String changeName = change.getName();
        switch (event.getEventType())
        {
            case OperationHistoryEvent.ABOUT_TO_EXECUTE:
                break;
            case OperationHistoryEvent.ABOUT_TO_UNDO:
                break;
            case OperationHistoryEvent.ABOUT_TO_REDO:
                break;
            case OperationHistoryEvent.DONE:
                break;
            case OperationHistoryEvent.UNDONE:
                //Proposal undone detected. Do something with the change.
                break;
            case OperationHistoryEvent.REDONE:
                break;
            case OperationHistoryEvent.OPERATION_NOT_OK:
                break;
            case OperationHistoryEvent.OPERATION_ADDED:
                break;
            case OperationHistoryEvent.OPERATION_REMOVED:
                break;
        }
    }
}