wro4j-core/src/main/java/ro/isdc/wro/model/resource/support/change/ResourceWatcher.java
private void checkResourceChange(final Resource resource, final Group group, final Callback callback,
      final AtomicBoolean isChanged)
      throws Exception {
    if (isChanged(resource, group.getName())) {
      isChanged.compareAndSet(false, true);
      callback.onResourceChanged(resource);
      lifecycleCallback.onResourceChanged(resource);
    }
  }
private void checkResourceChange(final Resource resource, final Group group, final Callback callback,
      final AtomicBoolean isChanged)
      throws Exception {
    if (isChanged(resource, group.getName())) {
      isChanged.compareAndSet(false, true);
      callback.onResourceChanged(resource);
      lifecycleCallback.onResourceChanged(resource);
    }
  }
Will check if a given resource was changed and will invoke the appropriate callback.