Java WatchKey.isValid方法代码示例

import java.nio.file.WatchKey; //导入方法依赖的package包/类
protected void watchDir(Path dir) throws IOException {
    LOG.debug("Registering watch for {}", dir);
    if (Thread.currentThread().isInterrupted()) {
        LOG.debug("Skipping adding watch since current thread is interrupted.");
    }

    // check if directory is already watched
    // on Windows, check if any parent is already watched
    for (Path path = dir; path != null; path = FILE_TREE_WATCHING_SUPPORTED ? path.getParent() : null) {
        WatchKey previousWatchKey = watchKeys.get(path);
        if (previousWatchKey != null && previousWatchKey.isValid()) {
            LOG.debug("Directory {} is already watched and the watch is valid, not adding another one.", path);
            return;
        }
    }

    int retryCount = 0;
    IOException lastException = null;
    while (retryCount++ < 2) {
        try {
            WatchKey watchKey = dir.register(watchService, WATCH_KINDS, WATCH_MODIFIERS);
            watchKeys.put(dir, watchKey);
            return;
        } catch (IOException e) {
            LOG.debug("Exception in registering for watching of " + dir, e);
            lastException = e;

            if (e instanceof NoSuchFileException) {
                LOG.debug("Return silently since directory doesn't exist.");
                return;
            }

            if (e instanceof FileSystemException && e.getMessage() != null && e.getMessage().contains("Bad file descriptor")) {
                // retry after getting "Bad file descriptor" exception
                LOG.debug("Retrying after 'Bad file descriptor'");
                continue;
            }

            // Windows at least will sometimes throw odd exceptions like java.nio.file.AccessDeniedException
            // if the file gets deleted while the watch is being set up.
            // So, we just ignore the exception if the dir doesn't exist anymore
            if (!Files.exists(dir)) {
                // return silently when directory doesn't exist
                LOG.debug("Return silently since directory doesn't exist.");
                return;
            } else {
                // no retry
                throw e;
            }
        }
    }
    LOG.debug("Retry count exceeded, throwing last exception");
    throw lastException;
}
 

import java.nio.file.WatchKey; //导入方法依赖的package包/类
private Set<File> filesFromEvents() throws InterruptedException {
  WatchKey key = watcher.take();
  Set<File> files = new LinkedHashSet<File>();
  if (key != null && key.isValid()) 
  {
    for (WatchEvent<?> event : key.pollEvents()) 
    {
      if (event.kind() == StandardWatchEventKinds.ENTRY_CREATE || event.kind() == StandardWatchEventKinds.ENTRY_MODIFY) 
      {
        Path item = (Path) event.context();
        File file = new File(((Path) key.watchable()).toAbsolutePath() + File.separator + item.getFileName());
        if (log.isDebugEnabled()) {
          log.debug("Watch Event: " + event.kind() + ": " + file);
        }
        if(isJarFile(file))
        {
          files.add(file);
        }
        else
          log.warn("[JAR Loader] Ignoring file "+file);
      }
      
    }
    key.reset();
   
  }
  return files;
}