Method addErrback

src/Deferred.java:751–754

Registers an "errback". If the deferred result is already available and is an exception, the errback is executed immediately from this thread. If the deferred result is already available and isn't an exception, the errback is discarded. If the deferred result is not available, this errback is qu

(final Callback<R, E> eb)

   * @return {@code this} with an "updated" type.
   */
  @SuppressWarnings("unchecked")
  public <R, E> Deferred<T> addErrback(final Callback<R, E> eb) {
    return addCallbacks((Callback<T, T>) ((Object) Callback.PASSTHROUGH), eb);
  }

  /**
   * Registers a callback both as a callback and as an "errback".