Java Waitable.await方法代码示例

import org.apache.hadoop.util.Waitable; //导入方法依赖的package包/类
/**
 * Fetch an existing ReplicaInfo object.
 *
 * @param key       The key that we're using.
 * @param waitable  The waitable object to wait on.
 * @return          The existing ReplicaInfo object, or null if there is
 *                  none.
 *
 * @throws RetriableException   If the caller needs to retry.
 */
private ShortCircuitReplicaInfo fetch(ExtendedBlockId key,
    Waitable<ShortCircuitReplicaInfo> waitable) throws RetriableException {
  // Another thread is already in the process of loading this
  // ShortCircuitReplica.  So we simply wait for it to complete.
  ShortCircuitReplicaInfo info;
  try {
    if (LOG.isTraceEnabled()) {
      LOG.trace(this + ": found waitable for " + key);
    }
    info = waitable.await();
  } catch (InterruptedException e) {
    LOG.info(this + ": interrupted while waiting for " + key);
    Thread.currentThread().interrupt();
    throw new RetriableException("interrupted");
  }
  if (info.getInvalidTokenException() != null) {
    LOG.info(this + ": could not get " + key + " due to InvalidToken " +
          "exception.", info.getInvalidTokenException());
    return info;
  }
  ShortCircuitReplica replica = info.getReplica();
  if (replica == null) {
    LOG.warn(this + ": failed to get " + key);
    return info;
  }
  if (replica.purged) {
    // Ignore replicas that have already been purged from the cache.
    throw new RetriableException("Ignoring purged replica " +
        replica + ".  Retrying.");
  }
  // Check if the replica is stale before using it.
  // If it is, purge it and retry.
  if (replica.isStale()) {
    LOG.info(this + ": got stale replica " + replica + ".  Removing " +
        "this replica from the replicaInfoMap and retrying.");
    // Remove the cache's reference to the replica.  This may or may not
    // trigger a close.
    purge(replica);
    throw new RetriableException("ignoring stale replica " + replica);
  }
  ref(replica);
  return info;
}
 

import org.apache.hadoop.util.Waitable; //导入方法依赖的package包/类
/**
 * Fetch an existing ReplicaInfo object.
 *
 * @param key       The key that we're using.
 * @param waitable  The waitable object to wait on.
 * @return          The existing ReplicaInfo object, or null if there is
 *                  none.
 *
 * @throws RetriableException   If the caller needs to retry.
 */
private ShortCircuitReplicaInfo fetch(ExtendedBlockId key,
    Waitable<ShortCircuitReplicaInfo> waitable) throws RetriableException {
  // Another thread is already in the process of loading this
  // ShortCircuitReplica.  So we simply wait for it to complete.
  ShortCircuitReplicaInfo info;
  try {
    LOG.trace("{}: found waitable for {}", this, key);
    info = waitable.await();
  } catch (InterruptedException e) {
    LOG.info(this + ": interrupted while waiting for " + key);
    Thread.currentThread().interrupt();
    throw new RetriableException("interrupted");
  }
  if (info.getInvalidTokenException() != null) {
    LOG.info(this + ": could not get " + key + " due to InvalidToken " +
        "exception.", info.getInvalidTokenException());
    return info;
  }
  ShortCircuitReplica replica = info.getReplica();
  if (replica == null) {
    LOG.warn(this + ": failed to get " + key);
    return info;
  }
  if (replica.purged) {
    // Ignore replicas that have already been purged from the cache.
    throw new RetriableException("Ignoring purged replica " +
        replica + ".  Retrying.");
  }
  // Check if the replica is stale before using it.
  // If it is, purge it and retry.
  if (replica.isStale()) {
    LOG.info(this + ": got stale replica " + replica + ".  Removing " +
        "this replica from the replicaInfoMap and retrying.");
    // Remove the cache's reference to the replica.  This may or may not
    // trigger a close.
    purge(replica);
    throw new RetriableException("ignoring stale replica " + replica);
  }
  ref(replica);
  return info;
}
 

import org.apache.hadoop.util.Waitable; //导入方法依赖的package包/类
/**
 * Fetch an existing ReplicaInfo object.
 *
 * @param key       The key that we're using.
 * @param waitable  The waitable object to wait on.
 * @return          The existing ReplicaInfo object, or null if there is
 *                  none.
 *
 * @throws RetriableException   If the caller needs to retry.
 */
private ShortCircuitReplicaInfo fetch(ExtendedBlockId key,
    Waitable<ShortCircuitReplicaInfo> waitable) throws RetriableException {
  // Another thread is already in the process of loading this
  // ShortCircuitReplica.  So we simply wait for it to complete.
  ShortCircuitReplicaInfo info;
  try {
    if (LOG.isTraceEnabled()) {
      LOG.trace(this + ": found waitable for " + key);
    }
    info = waitable.await();
  } catch (InterruptedException e) {
    LOG.info(this + ": interrupted while waiting for " + key);
    Thread.currentThread().interrupt();
    throw new RetriableException("interrupted");
  }
  if (info.getInvalidTokenException() != null) {
    LOG.warn(this + ": could not get " + key + " due to InvalidToken " +
          "exception.", info.getInvalidTokenException());
    return info;
  }
  ShortCircuitReplica replica = info.getReplica();
  if (replica == null) {
    LOG.warn(this + ": failed to get " + key);
    return info;
  }
  if (replica.purged) {
    // Ignore replicas that have already been purged from the cache.
    throw new RetriableException("Ignoring purged replica " +
        replica + ".  Retrying.");
  }
  // Check if the replica is stale before using it.
  // If it is, purge it and retry.
  if (replica.isStale()) {
    LOG.info(this + ": got stale replica " + replica + ".  Removing " +
        "this replica from the replicaInfoMap and retrying.");
    // Remove the cache's reference to the replica.  This may or may not
    // trigger a close.
    purge(replica);
    throw new RetriableException("ignoring stale replica " + replica);
  }
  ref(replica);
  return info;
}