queuedRebalanceMembers = null;
log.tracef("Rebalancing consistent hash for cache %s, members are %s", cacheName, newMembers);
int newTopologyId = cacheTopology.getTopologyId() + 1;
int newRebalanceId = cacheTopology.getRebalanceId() + 1;
ConsistentHash currentCH = cacheTopology.getCurrentCH();
if (currentCH == null) {
// There was one node in the cache before, and it left after the rebalance was triggered
// but before the rebalance actually started.
log.tracef("Ignoring request to rebalance cache %s, it doesn't have a consistent hash", cacheName);
return;
}
if (!expectedMembers.containsAll(newMembers)) {
newMembers.removeAll(expectedMembers);
log.tracef("Ignoring request to rebalance cache %s, we have new leavers: %s", cacheName, newMembers);
return;
}
ConsistentHashFactory chFactory = getJoinInfo().getConsistentHashFactory();
// This update will only add the joiners to the CH, we have already checked that we don't have leavers
ConsistentHash updatedMembersCH = chFactory.updateMembers(currentCH, newMembers, getCapacityFactors());
ConsistentHash balancedCH = chFactory.rebalance(updatedMembersCH);
if (balancedCH.equals(currentCH)) {
log.tracef("The balanced CH is the same as the current CH, not rebalancing");
return;
}
CacheTopology newTopology = new CacheTopology(newTopologyId, newRebalanceId, currentCH, balancedCH);
log.tracef("Updating cache %s topology for rebalance: %s", cacheName, newTopology);