public Object down(Message msg) {
Address dest = msg.getDest();
boolean multicast = dest == null;
if (msg.getSrc() == null) msg.setSrc(localAddress());
if (discard_all) {
if (dest == null || dest.equals(localAddress())) loopback(msg);
return null;
}
if (!multicast && drop_down_unicasts > 0) {
drop_down_unicasts = Math.max(0, drop_down_unicasts - 1);
return null;
}
if (multicast && drop_down_multicasts > 0) {
drop_down_multicasts = Math.max(0, drop_down_multicasts - 1);
return null;
}
if (down > 0) {
double r = Math.random();
if (r < down) {
if (excludeItself && dest != null && dest.equals(localAddress())) {
if (log.isTraceEnabled()) log.trace("excluding itself");
} else {
log.trace("dropping message");
num_down++;
return null;
}
}
}
return down_prot.down(msg);
}
/** Checks if a message should be passed up, or not */
protected boolean shouldDropUpMessage(
@SuppressWarnings("UnusedParameters") Message msg, Address sender) {
if (discard_all && !sender.equals(localAddress())) return true;
if (ignoredMembers.contains(sender)) {
if (log.isTraceEnabled()) log.trace(localAddress + ": dropping message from " + sender);
num_up++;
return true;
}
if (up > 0) {
double r = Math.random();
if (r < up) {
if (excludeItself && sender.equals(localAddress())) {
if (log.isTraceEnabled()) log.trace("excluding myself");
} else {
if (log.isTraceEnabled()) log.trace(localAddress + ": dropping message from " + sender);
num_up++;
return true;
}
}
}
return false;
}
/**
* 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;
}
}
/**
* 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()));
}
}