Java PersistenceUtils.serializeState方法代码示例

import com.google.ipc.invalidation.ticl.PersistenceUtils; //导入方法依赖的package包/类
/**
 * Handles receipt of a GCM message for a client that was unknown or not started. If the client
 * was unknown, drops the message. If the client was not started, rewrites the client's
 * persistent state to have a last-message-sent-time of 0, ensuring that the client will
 * send a heartbeat to the server when restarted. Since we drop the received GCM message,
 * the client will be disconnected by the invalidation pusher; this heartbeat ensures a
 * timely reconnection.
 */
private void handleGcmMessageForUnstartedClient(AndroidClientProxy proxy) {
  if (proxy == null) {
    // Unknown client; nothing to do.
    return;
  }

  // Client is not started. Open its storage. We are going to use unsafe calls here that
  // bypass the normal storage API. This is safe in this context because we hold a lock
  // that prevents anyone else from starting this client or accessing its storage. We
  // really should not be holding a lock across I/O, but at least this is only local
  // file I/O, and we're only writing a few bytes. Additionally, since we currently only
  // have one Ticl, we should only ever enter this function if we're not being used for
  // anything else.
  final String clientKey = proxy.getClientKey();
  logger.info("Received message for unloaded client; rewriting state file: %s", clientKey);

  // This storage must have been loaded, because we got this proxy from the client manager,
  // which always ensures that its entries have that property.
  AndroidStorage storageForClient = proxy.getStorage();
  PersistentTiclState clientState = decodeTiclState(clientKey, storageForClient);
  if (clientState == null) {
    // Logging done in decodeTiclState.
    return;
  }

  // Rewrite the last message sent time.
  PersistentTiclState newState = PersistentTiclState.newBuilder(clientState)
      .setLastMessageSendTimeMs(0).build();

  // Serialize the new state.
  byte[] newClientState = PersistenceUtils.serializeState(newState, digestFn);

  // Write it out.
  storageForClient.getPropertiesUnsafe().put(InvalidationClientCore.CLIENT_TOKEN_KEY,
      newClientState);
  storageForClient.storeUnsafe();
}