private HostConnectionPool addHost(Host host) {
try {
HostDistance distance = loadBalancer.distance(host);
if (distance == HostDistance.IGNORED) {
return pools.get(host);
} else {
logger.debug("Adding {} to list of queried hosts", host);
return pools.put(host, new HostConnectionPool(host, distance, this));
}
} catch (AuthenticationException e) {
logger.error("Error creating pool to {} ({})", host, e.getMessage());
host.getMonitor()
.signalConnectionFailure(new ConnectionException(e.getHost(), e.getMessage()));
return pools.get(host);
} catch (ConnectionException e) {
logger.debug("Error creating pool to {} ({})", host, e.getMessage());
host.getMonitor().signalConnectionFailure(e);
return pools.get(host);
}
}
/*
* When the set of live nodes change, the loadbalancer will change his
* mind on host distances. It might change it on the node that came/left
* but also on other nodes (for instance, if a node dies, another
* previously ignored node may be now considered).
*
* This method ensures that all hosts for which a pool should exist
* have one, and hosts that shouldn't don't.
*/
private void updateCreatedPools() {
for (Host h : cluster.getMetadata().allHosts()) {
HostDistance dist = loadBalancingPolicy().distance(h);
HostConnectionPool pool = pools.get(h);
if (pool == null) {
if (dist != HostDistance.IGNORED && h.getMonitor().isUp()) addOrRenewPool(h);
} else if (dist != pool.hostDistance) {
if (dist == HostDistance.IGNORED) {
removePool(h);
} else {
pool.hostDistance = dist;
}
}
}
}
public void onDown(Host host) {
loadBalancer.onDown(host);
HostConnectionPool pool = pools.remove(host);
// This should not be necessary but it's harmless
if (pool != null) pool.shutdown();
// If we've remove a host, the loadBalancer is allowed to change his mind on host distances.
for (Host h : cluster.getMetadata().allHosts()) {
if (!h.getMonitor().isUp()) continue;
HostDistance dist = loadBalancer.distance(h);
if (dist != HostDistance.IGNORED) {
HostConnectionPool p = pools.get(h);
if (p == null) addHost(host);
else p.hostDistance = dist;
}
}
}