/** Register the given directory with the WatchService */ private void register(Path dir) throws IOException { WatchKey key = dir.register(watcher, ENTRY_CREATE, ENTRY_DELETE, ENTRY_MODIFY); if (trace) { Path prev = keys.get(key); if (prev == null) { System.out.format("register: %s\n", dir); } else { if (!dir.equals(prev)) { System.out.format("update: %s -> %s\n", prev, dir); } } } keys.put(key, dir); }