Java Code Examples for com.twitter.util.Function#apply()

The following examples show how to use com.twitter.util.Function#apply() . You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example. You may check out the related API usage on the sidebar.
Example 1
Source File: ConfigFileWatcher.java    From singer with Apache License 2.0 6 votes vote down vote up 
/**
 * Adds a watch on the specified file. The file must exist, otherwise a FileNotFoundException
 * is returned. If the file is deleted after a watch is established, the watcher will log errors
 * but continue to monitor it, and resume watching if it is recreated.
 *
 * @param filePath path to the file to watch.
 * @param onUpdate function to call when a change is detected to the file. The entire contents
 *                 of the file will be passed in to the function. Note that onUpdate will be
 *                 called once before this call completes, which facilities initial load of data.
 *                 This callback is executed synchronously on the watcher thread - it is
 *                 important that the function be non-blocking.
 */
public synchronized void addWatch(String filePath, Function<byte[], Void> onUpdate)
    throws IOException {
  MorePreconditions.checkNotBlank(filePath);
  Preconditions.checkNotNull(onUpdate);

  // Read the file and make the initial onUpdate call.
  File file = new File(filePath);
  ByteSource byteSource = Files.asByteSource(file);
  onUpdate.apply(byteSource.read());

  // Add the file to our map if it isn't already there, and register the new change watcher.
  ConfigFileInfo configFileInfo = watchedFileMap.get(filePath);
  if (configFileInfo == null) {
    configFileInfo = new ConfigFileInfo(file.lastModified(), byteSource.hash(HASH_FUNCTION));
    watchedFileMap.put(filePath, configFileInfo);
  }
  configFileInfo.changeWatchers.add(onUpdate);
}
Example 2
Source File: ConfigFileWatcher.java    From pinlater with Apache License 2.0 6 votes vote down vote up 
/**
 * Adds a watch on the specified file. The file must exist, otherwise a FileNotFoundException
 * is returned. If the file is deleted after a watch is established, the watcher will log errors
 * but continue to monitor it, and resume watching if it is recreated.
 *
 * @param filePath path to the file to watch.
 * @param onUpdate function to call when a change is detected to the file. The entire contents
 *                 of the file will be passed in to the function. Note that onUpdate will be
 *                 called once before this call completes, which facilities initial load of data.
 *                 This callback is executed synchronously on the watcher thread - it is
 *                 important that the function be non-blocking.
 */
public synchronized void addWatch(String filePath, Function<byte[], Void> onUpdate)
    throws IOException {
  MorePreconditions.checkNotBlank(filePath);
  Preconditions.checkNotNull(onUpdate);

  // Read the file and make the initial onUpdate call.
  File file = new File(filePath);
  ByteSource byteSource = Files.asByteSource(file);
  onUpdate.apply(byteSource.read());

  // Add the file to our map if it isn't already there, and register the new change watcher.
  ConfigFileInfo configFileInfo = watchedFileMap.get(filePath);
  if (configFileInfo == null) {
    configFileInfo = new ConfigFileInfo(file.lastModified(), byteSource.hash(HASH_FUNCTION));
    watchedFileMap.put(filePath, configFileInfo);
  }
  configFileInfo.changeWatchers.add(onUpdate);
}
Example 3
Source File: RedisUtils.java    From pinlater with Apache License 2.0 6 votes vote down vote up 
/**
 * Gets the connection from the connection pool and adds the wrapper catch/finally block for the
 * given function.
 *
 * This helper method saves the trouble of dealing with redis connection. When we got
 * JedisConnectionException, we will discard this connection. Otherwise, we return the connection
 * to the connection pool.
 *
 * @param jedisPool Jedis connection pool
 * @param redisDBNum Redis DB number (index) (if redisDBNum == -1, don't select a DB )
 * @param func    The function to execute inside the catch/finally block.
 * @return A Resp object, which is the return value of wrapped function.
 */
public static <Resp> Resp executeWithConnection(JedisPool jedisPool,
                                                int redisDBNum,
                                                Function<Jedis, Resp> func) {
  Preconditions.checkNotNull(jedisPool);
  Preconditions.checkNotNull(func);
  Jedis conn = null;
  boolean gotJedisConnException = false;
  try {
    conn = jedisPool.getResource();
    selectRedisDB(conn, redisDBNum);
    return func.apply(conn);
  } catch (JedisConnectionException e) {
    jedisPool.returnBrokenResource(conn);
    gotJedisConnException = true;
    throw e;
  } finally {
    if (conn != null && !gotJedisConnException) {
      jedisPool.returnResource(conn);
    }
  }
}