protected <T> GroupRequest<T> cast(
      final Collection<Address> dests,
      Message msg,
      RequestOptions options,
      boolean block_for_results,
      FutureListener<RspList<T>> listener)
      throws Exception {
    if (msg.getDest() != null && !(msg.getDest() instanceof AnycastAddress))
      throw new IllegalArgumentException("message destination is non-null, cannot send message");

    if (options != null) {
      msg.setFlag(options.getFlags()).setTransientFlag(options.getTransientFlags());
      if (options.getScope() > 0) msg.setScope(options.getScope());
    }

    List<Address> real_dests;
    // we need to clone because we don't want to modify the original
    if (dests != null) {
      real_dests = new ArrayList<Address>();
      for (Address dest : dests) {
        if (dest instanceof SiteAddress || this.members.contains(dest)) {
          if (!real_dests.contains(dest)) real_dests.add(dest);
        }
      }
    } else real_dests = new ArrayList<Address>(members);

    // if local delivery is off, then we should not wait for the message from the local member.
    // therefore remove it from the membership
    Channel tmp = channel;
    if ((tmp != null && tmp.getDiscardOwnMessages())
        || msg.isTransientFlagSet(Message.TransientFlag.DONT_LOOPBACK)) {
      if (local_addr == null) local_addr = tmp != null ? tmp.getAddress() : null;
      if (local_addr != null) real_dests.remove(local_addr);
    }

    if (options != null && options.hasExclusionList()) {
      Address[] exclusion_list = options.exclusionList();
      for (Address excluding : exclusion_list) real_dests.remove(excluding);
    }

    // don't even send the message if the destination list is empty
    if (log.isTraceEnabled()) log.trace("real_dests=" + real_dests);

    if (real_dests.isEmpty()) {
      if (log.isTraceEnabled()) log.trace("destination list is empty, won't send message");
      return null;
    }

    if (options != null) {
      boolean async = options.getMode() == ResponseMode.GET_NONE;
      if (options.getAnycasting()) {
        if (async) async_anycasts.incrementAndGet();
        else sync_anycasts.incrementAndGet();
      } else {
        if (async) async_multicasts.incrementAndGet();
        else sync_multicasts.incrementAndGet();
      }
    }

    GroupRequest<T> req = new GroupRequest<T>(msg, corr, real_dests, options);
    if (listener != null) req.setListener(listener);
    if (options != null) {
      req.setResponseFilter(options.getRspFilter());
      req.setAnycasting(options.getAnycasting());
    }
    req.setBlockForResults(block_for_results);
    req.execute();
    return req;
  }
 /**
  * Sends a message to all members and expects responses from members in dests (if non-null).
  *
  * @param dests A list of group members from which to expect responses (if the call is blocking).
  * @param msg The message to be sent
  * @param options A set of options that govern the call. See {@link
  *     org.jgroups.blocks.RequestOptions} for details
  * @return RspList A list of Rsp elements
  * @throws Exception If the request cannot be sent
  * @since 2.9
  */
 public <T> RspList<T> castMessage(
     final Collection<Address> dests, Message msg, RequestOptions options) throws Exception {
   GroupRequest<T> req = cast(dests, msg, options, true);
   return req != null ? req.getResults() : new RspList();
 }