Beispiel #1
0
  /**
   * Tests A|6, A|7, A|8 and B|7, B|8, B|9 -> we should have a subviews in MergeView consisting of
   * only 2 elements: A|5 and B|5
   */
  public void testMultipleViewsBySameMembers() throws Exception {
    View a1 =
        View.create(
            a.getAddress(),
            6,
            a.getAddress(),
            b.getAddress(),
            c.getAddress(),
            d.getAddress()); // {A,B,C,D}
    View a2 =
        View.create(a.getAddress(), 7, a.getAddress(), b.getAddress(), c.getAddress()); // {A,B,C}
    View a3 = View.create(a.getAddress(), 8, a.getAddress(), b.getAddress()); // {A,B}
    View a4 = View.create(a.getAddress(), 9, a.getAddress()); // {A}

    View b1 = View.create(b.getAddress(), 7, b.getAddress(), c.getAddress(), d.getAddress());
    View b2 = View.create(b.getAddress(), 8, b.getAddress(), c.getAddress());
    View b3 = View.create(b.getAddress(), 9, b.getAddress());

    Util.close(c, d); // not interested in those...

    // A and B cannot communicate:
    discard(true, a, b);

    // inject view A|6={A} into A and B|5={B} into B
    injectView(a4, a);
    injectView(b3, b);

    assert a.getView().equals(a4);
    assert b.getView().equals(b3);

    List<Event> merge_events = new ArrayList<>();
    for (View view : Arrays.asList(a3, a4, a2, a1)) {
      MERGE3.MergeHeader hdr = MERGE3.MergeHeader.createInfo(view.getViewId(), null, null);
      Message msg = new Message(null, a.getAddress(), null).putHeader(merge_id, hdr);
      merge_events.add(new Event(Event.MSG, msg));
    }
    for (View view : Arrays.asList(b2, b3, b1)) {
      MERGE3.MergeHeader hdr = MERGE3.MergeHeader.createInfo(view.getViewId(), null, null);
      Message msg = new Message(null, b.getAddress(), null).putHeader(merge_id, hdr);
      merge_events.add(new Event(Event.MSG, msg));
    }

    // A and B can communicate again
    discard(false, a, b);

    injectMergeEvents(merge_events, a, b);
    checkInconsistencies(a, b); // merge will happen between A and B
    Util.waitUntilAllChannelsHaveSameSize(10000, 500, a, b);
    System.out.println("A's view: " + a.getView() + "\nB's view: " + b.getView());
    assert a.getView().size() == 2;
    assert a.getView().containsMember(a.getAddress());
    assert a.getView().containsMember(b.getAddress());
    assert a.getView().equals(b.getView());
    for (View merge_view : Arrays.asList(getViewFromGMS(a), getViewFromGMS(b))) {
      System.out.println(merge_view);
      assert merge_view instanceof MergeView;
      List<View> subviews = ((MergeView) merge_view).getSubgroups();
      assert subviews.size() == 2;
    }
  }
Beispiel #2
0
  /** Tests a merge between ViewIds of the same coord, e.g. A|6, A|7, A|8, A|9 */
  public void testViewsBySameCoord() {
    View v1 =
        View.create(
            a.getAddress(),
            6,
            a.getAddress(),
            b.getAddress(),
            c.getAddress(),
            d.getAddress()); // {A,B,C,D}
    View v2 =
        View.create(a.getAddress(), 7, a.getAddress(), b.getAddress(), c.getAddress()); // {A,B,C}
    View v3 = View.create(a.getAddress(), 8, a.getAddress(), b.getAddress()); // {A,B}
    View v4 = View.create(a.getAddress(), 9, a.getAddress()); // {A}

    Util.close(b, c, d); // not interested in those...

    MERGE3 merge = (MERGE3) a.getProtocolStack().findProtocol(MERGE3.class);
    for (View view : Arrays.asList(v1, v2, v4, v3)) {
      MERGE3.MergeHeader hdr = MERGE3.MergeHeader.createInfo(view.getViewId(), null, null);
      Message msg = new Message(null, a.getAddress(), null).putHeader(merge.getId(), hdr);
      merge.up(new Event(Event.MSG, msg));
    }

    merge.checkInconsistencies(); // no merge will happen

    Util.waitUntilAllChannelsHaveSameSize(10000, 500, a);
    System.out.println("A's view: " + a.getView());
    assert a.getView().size() == 1;
    assert a.getView().containsMember(a.getAddress());
  }
Beispiel #3
0
  protected void sendDiscoveryResponse(
      Address logical_addr,
      List<PhysicalAddress> physical_addrs,
      boolean is_server,
      boolean return_view_only,
      String logical_name,
      final Address sender) {
    PingData data;
    if (return_view_only) {
      data = new PingData(logical_addr, view, is_server, null, null);
    } else {
      ViewId view_id = view != null ? view.getViewId() : null;
      data = new PingData(logical_addr, null, view_id, is_server, logical_name, physical_addrs);
    }

    final Message rsp_msg = new Message(sender, null, null);
    rsp_msg.setFlag(Message.OOB);
    final PingHeader rsp_hdr = new PingHeader(PingHeader.GET_MBRS_RSP, data);
    rsp_msg.putHeader(this.id, rsp_hdr);

    if (stagger_timeout > 0) {
      int view_size = view != null ? view.size() : 10;
      int rank = Util.getRank(view, local_addr); // returns 0 if view or local_addr are null
      long sleep_time =
          rank == 0
              ? Util.random(stagger_timeout)
              : stagger_timeout * rank / view_size - (stagger_timeout / view_size);
      timer.schedule(
          new Runnable() {
            public void run() {
              if (log.isTraceEnabled())
                log.trace(
                    local_addr
                        + ": received GET_MBRS_REQ from "
                        + sender
                        + ", sending staggered response "
                        + rsp_hdr);
              down_prot.down(new Event(Event.MSG, rsp_msg));
            }
          },
          sleep_time,
          TimeUnit.MILLISECONDS);
      return;
    }

    if (log.isTraceEnabled())
      log.trace("received GET_MBRS_REQ from " + sender + ", sending response " + rsp_hdr);
    down_prot.down(new Event(Event.MSG, rsp_msg));
  }
Beispiel #4
0
  /**
   * Computes the next view. Returns a copy that has <code>old_mbrs</code> and <code>suspected_mbrs
   * </code> removed and <code>new_mbrs</code> added.
   */
  public View getNextView(
      Collection<Address> new_mbrs,
      Collection<Address> old_mbrs,
      Collection<Address> suspected_mbrs) {
    synchronized (members) {
      ViewId view_id = view != null ? view.getViewId() : null;
      if (view_id == null) {
        log.error("view_id is null");
        return null; // this should *never* happen !
      }
      long vid = Math.max(view_id.getId(), ltime) + 1;
      ltime = vid;
      Membership tmp_mbrs = tmp_members.copy(); // always operate on the temporary membership
      tmp_mbrs.remove(suspected_mbrs);
      tmp_mbrs.remove(old_mbrs);
      tmp_mbrs.add(new_mbrs);
      List<Address> mbrs = tmp_mbrs.getMembers();
      Address new_coord = local_addr;
      if (!mbrs.isEmpty()) new_coord = mbrs.get(0);
      View v = new View(new_coord, vid, mbrs);

      // Update membership (see DESIGN for explanation):
      tmp_members.set(mbrs);

      // Update joining list (see DESIGN for explanation)
      if (new_mbrs != null) {
        for (Address tmp_mbr : new_mbrs) {
          if (!joining.contains(tmp_mbr)) joining.add(tmp_mbr);
        }
      }

      // Update leaving list (see DESIGN for explanations)
      if (old_mbrs != null) {
        for (Address addr : old_mbrs) {
          if (!leaving.contains(addr)) leaving.add(addr);
        }
      }
      if (suspected_mbrs != null) {
        for (Address addr : suspected_mbrs) {
          if (!leaving.contains(addr)) leaving.add(addr);
        }
      }
      return v;
    }
  }
Beispiel #5
0
  /** A: {A,B} B: {A,B} C: {C} C receives INFO from B only */
  public void testMergeWithIncompleteInfos() throws Exception {
    Util.close(d);
    enableInfoSender(false, a, b, c);
    View one = View.create(a.getAddress(), 10, a.getAddress(), b.getAddress());
    View two = View.create(c.getAddress(), 10, c.getAddress());
    injectView(one, a, b);
    injectView(two, c);
    enableInfoSender(false, a, b, c);

    Util.waitUntilAllChannelsHaveSameSize(10000, 500, a, b);
    Util.waitUntilAllChannelsHaveSameSize(10000, 500, c);
    System.out.printf("\nPartitions:\n");
    for (JChannel ch : Arrays.asList(a, b, c))
      System.out.println(ch.getName() + ": " + ch.getView());

    MERGE3.MergeHeader hdr = MERGE3.MergeHeader.createInfo(one.getViewId(), null, null);
    Message msg =
        new Message(null, b.getAddress(), null)
            .putHeader(merge_id, hdr); // B sends the INFO message to C
    Event merge_event = new Event(Event.MSG, msg);
    MERGE3 merge = (MERGE3) c.getProtocolStack().findProtocol(MERGE3.class);
    merge.up(merge_event);
    enableInfoSender(true, a, b, c);
    System.out.println("\nEnabling INFO sending in merge protocols to merge subclusters");

    Util.waitUntilAllChannelsHaveSameSize(30000, 1000, a, b, c);
    System.out.println("\nResulting views:");
    for (JChannel ch : Arrays.asList(a, b, c)) {
      GMS gms = (GMS) ch.getProtocolStack().findProtocol(GMS.class);
      View mv = gms.view();
      System.out.println(mv);
    }
    for (JChannel ch : Arrays.asList(a, b, c)) {
      GMS gms = (GMS) ch.getProtocolStack().findProtocol(GMS.class);
      View mv = gms.view();
      assert mv instanceof MergeView;
      assert mv.size() == 3;
      assert ((MergeView) mv).getSubgroups().size() == 2;
    }
    for (JChannel ch : Arrays.asList(a, b, c)) {
      View view = ch.getView();
      assert view.size() == 3 : "view should have 3 members: " + view;
    }
  }
Beispiel #6
0
  /**
   * An event was received from the layer below. Usually the current layer will want to examine the
   * event type and - depending on its type - perform some computation (e.g. removing headers from a
   * MSG event type, or updating the internal membership list when receiving a VIEW_CHANGE event).
   * Finally the event is either a) discarded, or b) an event is sent down the stack using <code>
   * PassDown</code> or c) the event (or another event) is sent up the stack using <code>PassUp
   * </code>.
   *
   * <p>For the PING protocol, the Up operation does the following things. 1. If the event is a
   * Event.MSG then PING will inspect the message header. If the header is null, PING simply passes
   * up the event If the header is PingHeader.GET_MBRS_REQ then the PING protocol will PassDown a
   * PingRequest message If the header is PingHeader.GET_MBRS_RSP we will add the message to the
   * initial members vector and wake up any waiting threads. 2. If the event is Event.SET_LOCAL_ADDR
   * we will simple set the local address of this protocol 3. For all other messages we simple pass
   * it up to the protocol above
   *
   * @param evt - the event that has been sent from the layer below
   */
  @SuppressWarnings("unchecked")
  public Object up(Event evt) {

    switch (evt.getType()) {
      case Event.MSG:
        Message msg = (Message) evt.getArg();
        PingHeader hdr = (PingHeader) msg.getHeader(this.id);
        if (hdr == null) return up_prot.up(evt);

        PingData data = hdr.data;
        Address logical_addr = data != null ? data.getAddress() : null;

        if (is_leaving) return null; // prevents merging back a leaving member
        // (https://issues.jboss.org/browse/JGRP-1336)

        switch (hdr.type) {
          case PingHeader.GET_MBRS_REQ: // return Rsp(local_addr, coord)
            if (group_addr == null || hdr.cluster_name == null) {
              if (log.isWarnEnabled())
                log.warn(
                    "group_addr ("
                        + group_addr
                        + ") or cluster_name of header ("
                        + hdr.cluster_name
                        + ") is null; passing up discovery request from "
                        + msg.getSrc()
                        + ", but this should not"
                        + " be the case");
            } else {
              if (!group_addr.equals(hdr.cluster_name)) {
                if (log.isWarnEnabled())
                  log.warn(
                      "discarding discovery request for cluster '"
                          + hdr.cluster_name
                          + "' from "
                          + msg.getSrc()
                          + "; our cluster name is '"
                          + group_addr
                          + "'. "
                          + "Please separate your clusters cleanly.");
                return null;
              }
            }

            // add physical address and logical name of the discovery sender (if available) to the
            // cache
            if (data != null) {
              if (logical_addr == null) logical_addr = msg.getSrc();
              Collection<PhysicalAddress> physical_addrs = data.getPhysicalAddrs();
              PhysicalAddress physical_addr =
                  physical_addrs != null && !physical_addrs.isEmpty()
                      ? physical_addrs.iterator().next()
                      : null;
              if (logical_addr != null && physical_addr != null)
                down(
                    new Event(
                        Event.SET_PHYSICAL_ADDRESS,
                        new Tuple<Address, PhysicalAddress>(logical_addr, physical_addr)));
              if (logical_addr != null && data.getLogicalName() != null)
                UUID.add(logical_addr, data.getLogicalName());
              discoveryRequestReceived(msg.getSrc(), data.getLogicalName(), physical_addrs);

              synchronized (ping_responses) {
                for (Responses response : ping_responses) {
                  response.addResponse(data, false);
                }
              }
            }

            if (hdr.view_id != null) {
              // If the discovery request is merge-triggered, and the ViewId shipped with it
              // is the same as ours, we don't respond (JGRP-1315).
              ViewId my_view_id = view != null ? view.getViewId() : null;
              if (my_view_id != null && my_view_id.equals(hdr.view_id)) return null;

              boolean send_discovery_rsp =
                  force_sending_discovery_rsps
                      || is_coord
                      || current_coord == null
                      || current_coord.equals(msg.getSrc());
              if (!send_discovery_rsp) {
                if (log.isTraceEnabled())
                  log.trace(
                      local_addr
                          + ": suppressing merge response as I'm not a coordinator and the "
                          + "discovery request was not sent by a coordinator");
                return null;
              }
            }

            if (isMergeRunning()) {
              if (log.isTraceEnabled())
                log.trace(
                    local_addr + ": suppressing merge response as a merge is already in progress");
              return null;
            }

            List<PhysicalAddress> physical_addrs =
                hdr.view_id != null
                    ? null
                    : Arrays.asList(
                        (PhysicalAddress) down(new Event(Event.GET_PHYSICAL_ADDRESS, local_addr)));
            sendDiscoveryResponse(
                local_addr,
                physical_addrs,
                is_server,
                hdr.view_id != null,
                UUID.get(local_addr),
                msg.getSrc());
            return null;

          case PingHeader.GET_MBRS_RSP: // add response to vector and notify waiting thread
            // add physical address (if available) to transport's cache
            if (data != null) {
              Address response_sender = msg.getSrc();
              if (logical_addr == null) logical_addr = msg.getSrc();
              Collection<PhysicalAddress> addrs = data.getPhysicalAddrs();
              PhysicalAddress physical_addr =
                  addrs != null && !addrs.isEmpty() ? addrs.iterator().next() : null;
              if (logical_addr != null && physical_addr != null)
                down(
                    new Event(
                        Event.SET_PHYSICAL_ADDRESS,
                        new Tuple<Address, PhysicalAddress>(logical_addr, physical_addr)));
              if (logical_addr != null && data.getLogicalName() != null)
                UUID.add(logical_addr, data.getLogicalName());

              if (log.isTraceEnabled())
                log.trace(
                    local_addr + ": received GET_MBRS_RSP from " + response_sender + ": " + data);
              boolean overwrite = logical_addr != null && logical_addr.equals(response_sender);
              synchronized (ping_responses) {
                for (Responses response : ping_responses) {
                  response.addResponse(data, overwrite);
                }
              }
            }
            return null;

          default:
            if (log.isWarnEnabled())
              log.warn("got PING header with unknown type (" + hdr.type + ')');
            return null;
        }

      case Event.GET_PHYSICAL_ADDRESS:
        try {
          sendDiscoveryRequest(group_addr, null, null);
        } catch (InterruptedIOException ie) {
          if (log.isWarnEnabled()) {
            log.warn("Discovery request for cluster " + group_addr + " interrupted");
          }
          Thread.currentThread().interrupt();
        } catch (Exception ex) {
          if (log.isErrorEnabled()) log.error("failed sending discovery request", ex);
        }
        return null;

      case Event.FIND_INITIAL_MBRS: // sent by transport
        return findInitialMembers(null);
    }

    return up_prot.up(evt);
  }
Beispiel #7
0
 public ViewId getViewId() {
   return view != null ? view.getViewId() : null;
 }
Beispiel #8
0
 @ManagedAttribute
 public String getView() {
   return view != null ? view.getViewId().toString() : "null";
 }
Beispiel #9
0
  /**
   * Callback method <br>
   * Called by the ProtocolStack when a message is received.
   *
   * @param evt the event carrying the message from the protocol stack
   */
  public Object up(Event evt) {
    switch (evt.getType()) {
      case Event.MSG:
        Message msg = (Message) evt.getArg();
        if (stats) {
          received_msgs++;
          received_bytes += msg.getLength();
        }

        // discard local messages (sent by myself to me)
        if (discard_own_messages
            && local_addr != null
            && msg.getSrc() != null
            && local_addr.equals(msg.getSrc())) return null;
        break;

      case Event.VIEW_CHANGE:
        View tmp = (View) evt.getArg();
        if (tmp instanceof MergeView) my_view = new View(tmp.getViewId(), tmp.getMembers());
        else my_view = tmp;

        // Bela&Vladimir Oct 27th,2006 (JGroups 2.4): we need to set connected=true because a client
        // can
        // call channel.getView() in viewAccepted() callback invoked on this thread (see
        // Event.VIEW_CHANGE handling below)

        // not good: we are only connected when we returned from connect() - bela June 22 2007
        // Changed: when a channel gets a view of which it is a member then it should be
        // connected even if connect() hasn't returned yet ! (bela Noc 2010)
        if (state != State.CONNECTED) state = State.CONNECTED;
        break;

      case Event.CONFIG:
        Map<String, Object> cfg = (Map<String, Object>) evt.getArg();
        if (cfg != null) {
          if (cfg.containsKey("state_transfer")) {
            state_transfer_supported = (Boolean) cfg.get("state_transfer");
          }
          if (cfg.containsKey("flush_supported")) {
            flush_supported = (Boolean) cfg.get("flush_supported");
          }
        }
        break;

      case Event.GET_STATE_OK:
        StateTransferResult result = (StateTransferResult) evt.getArg();
        if (up_handler != null) {
          try {
            Object retval = up_handler.up(evt);
            state_promise.setResult(new StateTransferResult());
            return retval;
          } catch (Throwable t) {
            state_promise.setResult(new StateTransferResult(t));
          }
        }

        if (receiver != null) {
          try {
            if (result.hasBuffer()) {
              byte[] tmp_state = result.getBuffer();
              ByteArrayInputStream input = new ByteArrayInputStream(tmp_state);
              receiver.setState(input);
            }
            state_promise.setResult(result);
          } catch (Throwable t) {
            state_promise.setResult(new StateTransferResult(t));
          }
        }
        break;

      case Event.STATE_TRANSFER_INPUTSTREAM_CLOSED:
        state_promise.setResult((StateTransferResult) evt.getArg());
        break;

      case Event.STATE_TRANSFER_INPUTSTREAM:
        // Oct 13,2006 moved to down() when Event.STATE_TRANSFER_INPUTSTREAM_CLOSED is received
        // state_promise.setResult(is != null? Boolean.TRUE : Boolean.FALSE);

        if (up_handler != null) return up_handler.up(evt);

        InputStream is = (InputStream) evt.getArg();
        if (is != null && receiver != null) {
          try {
            receiver.setState(is);
          } catch (Throwable t) {
            throw new RuntimeException("failed calling setState() in state requester", t);
          }
        }
        break;

      case Event.STATE_TRANSFER_OUTPUTSTREAM:
        if (receiver != null && evt.getArg() != null) {
          try {
            receiver.getState((OutputStream) evt.getArg());
          } catch (Exception e) {
            throw new RuntimeException("failed calling getState() in state provider", e);
          }
        }
        break;

      case Event.GET_LOCAL_ADDRESS:
        return local_addr;

      default:
        break;
    }

    // If UpHandler is installed, pass all events to it and return (UpHandler is e.g. a building
    // block)
    if (up_handler != null) return up_handler.up(evt);

    if (receiver != null) return invokeCallback(evt.getType(), evt.getArg());
    return null;
  }
Beispiel #10
0
  /**
   * Sets the new view and sends a VIEW_CHANGE event up and down the stack. If the view is a
   * MergeView (subclass of View), then digest will be non-null and has to be set before installing
   * the view.
   */
  public void installView(View new_view, Digest digest) {
    ViewId vid = new_view.getVid();
    List<Address> mbrs = new_view.getMembers();
    ltime =
        Math.max(
            vid.getId(),
            ltime); // compute the logical time, regardless of whether the view is accepted

    // Discards view with id lower than or equal to our own. Will be installed without check if it
    // is the first view
    if (view != null) {
      ViewId view_id = view.getViewId();
      int rc = vid.compareToIDs(view_id);
      if (rc <= 0) {
        if (log.isWarnEnabled()
            && rc < 0
            && log_view_warnings) { // only scream if view is smaller, silently discard same views
          log.warn(
              local_addr
                  + ": received view < current view;"
                  + " discarding it (current vid: "
                  + view_id
                  + ", new vid: "
                  + vid
                  + ')');
        }
        return;
      }
    }

    /* Check for self-inclusion: if I'm not part of the new membership, I just discard it.
    This ensures that messages sent in view V1 are only received by members of V1 */
    if (!mbrs.contains(local_addr)) {
      if (log.isWarnEnabled() && log_view_warnings)
        log.warn(local_addr + ": not member of view " + new_view.getViewId() + "; discarding it");
      return;
    }

    if (digest != null) {
      if (new_view instanceof MergeView) mergeDigest(digest);
      else setDigest(digest);
    }

    if (log.isDebugEnabled()) log.debug(local_addr + ": installing view " + new_view);

    Event view_event;
    synchronized (members) {
      view = new View(new_view.getVid(), new_view.getMembers());
      view_event = new Event(Event.VIEW_CHANGE, new_view);

      // Set the membership. Take into account joining members
      if (!mbrs.isEmpty()) {
        members.set(mbrs);
        tmp_members.set(members);
        joining.removeAll(mbrs); // remove all members in mbrs from joining
        // remove all elements from 'leaving' that are not in 'mbrs'
        leaving.retainAll(mbrs);

        tmp_members.add(joining); // add members that haven't yet shown up in the membership
        tmp_members.remove(
            leaving); // remove members that haven't yet been removed from the membership

        // add to prev_members
        for (Address addr : mbrs) {
          if (!prev_members.contains(addr)) prev_members.add(addr);
        }
      }

      Address coord = determineCoordinator();
      if (coord != null && coord.equals(local_addr) && !haveCoordinatorRole()) {
        becomeCoordinator();
      } else {
        if (haveCoordinatorRole() && !local_addr.equals(coord)) {
          becomeParticipant();
          merge_ack_collector.reset(null); // we don't need this one anymore
        }
      }
    }

    // - Changed order of passing view up and down (http://jira.jboss.com/jira/browse/JGRP-347)
    // - Changed it back (bela Sept 4 2007): http://jira.jboss.com/jira/browse/JGRP-564
    // - Moved sending up view_event out of the synchronized block (bela Nov 2011)
    down_prot.down(view_event); // needed e.g. by failure detector or UDP
    up_prot.up(view_event);

    List<Address> tmp_mbrs = new_view.getMembers();
    ack_collector.retainAll(tmp_mbrs);
    merge_ack_collector.retainAll(tmp_mbrs);

    if (new_view instanceof MergeView) merger.forceCancelMerge();

    if (stats) {
      num_views++;
      prev_views.add(new Tuple<View, Long>(new_view, System.currentTimeMillis()));
    }
  }
Beispiel #11
0
  /**
   * Broadcasts the new view and digest, and waits for acks from all members in the list given as
   * argument. If the list is null, we take the members who are part of new_view
   */
  public void castViewChange(
      View new_view, Digest digest, JoinRsp jr, Collection<Address> newMembers) {
    if (log.isTraceEnabled())
      log.trace(local_addr + ": mcasting view " + new_view + " (" + new_view.size() + " mbrs)\n");

    // Send down a local TMP_VIEW event. This is needed by certain layers (e.g. NAKACK) to compute
    // correct digest
    // in case client's next request (e.g. getState()) reaches us *before* our own view change
    // multicast.
    // Check NAKACK's TMP_VIEW handling for details
    down_prot.up(new Event(Event.TMP_VIEW, new_view));
    down_prot.down(new Event(Event.TMP_VIEW, new_view));

    List<Address> ackMembers = new ArrayList<Address>(new_view.getMembers());
    if (newMembers != null && !newMembers.isEmpty()) ackMembers.removeAll(newMembers);

    Message view_change_msg = new Message(); // bcast to all members
    GmsHeader hdr = new GmsHeader(GmsHeader.VIEW, new_view);
    hdr.my_digest = digest;
    view_change_msg.putHeader(this.id, hdr);

    // If we're the only member the VIEW is broadcast to, let's simply install the view directly,
    // without
    // sending the VIEW multicast ! Or else N-1 members drop the multicast anyway...
    if (local_addr != null && ackMembers.size() == 1 && ackMembers.get(0).equals(local_addr)) {
      // we need to add the message to the retransmit window (e.g. in NAKACK), so (1) it can be
      // retransmitted and
      // (2) we increment the seqno (otherwise, we'd return an incorrect digest)
      down_prot.down(new Event(Event.ADD_TO_XMIT_TABLE, view_change_msg));
      impl.handleViewChange(new_view, digest);
    } else {
      if (!ackMembers.isEmpty()) ack_collector.reset(ackMembers);

      down_prot.down(new Event(Event.MSG, view_change_msg));
      try {
        if (!ackMembers.isEmpty()) {
          ack_collector.waitForAllAcks(view_ack_collection_timeout);
          if (log.isTraceEnabled())
            log.trace(
                local_addr
                    + ": received all "
                    + ack_collector.expectedAcks()
                    + " ACKs from members for view "
                    + new_view.getVid());
        }
      } catch (TimeoutException e) {
        if (log_collect_msgs && log.isWarnEnabled()) {
          log.warn(
              local_addr
                  + ": failed to collect all ACKs (expected="
                  + ack_collector.expectedAcks()
                  + ") for view "
                  + new_view.getViewId()
                  + " after "
                  + view_ack_collection_timeout
                  + "ms, missing ACKs from "
                  + ack_collector.printMissing());
        }
      }
    }

    if (jr != null && (newMembers != null && !newMembers.isEmpty())) {
      ack_collector.reset(new ArrayList<Address>(newMembers));
      for (Address joiner : newMembers) {
        sendJoinResponse(jr, joiner);
      }
      try {
        ack_collector.waitForAllAcks(view_ack_collection_timeout);
        if (log.isTraceEnabled())
          log.trace(
              local_addr
                  + ": received all ACKs ("
                  + ack_collector.expectedAcks()
                  + ") from joiners for view "
                  + new_view.getVid());
      } catch (TimeoutException e) {
        if (log_collect_msgs && log.isWarnEnabled()) {
          log.warn(
              local_addr
                  + ": failed to collect all ACKs (expected="
                  + ack_collector.expectedAcks()
                  + ") for unicast view "
                  + new_view
                  + " after "
                  + view_ack_collection_timeout
                  + "ms, missing ACKs from "
                  + ack_collector.printMissing());
        }
      }
    }
  }