@Override
public void initWithNiwsConfig(IClientConfig clientConfig) {
predicate =
CompositePredicate.withPredicate(new AvailabilityPredicate(this, clientConfig))
.addFallbackPredicate(AbstractServerPredicate.alwaysTrue())
.build();
}
public AvailabilityFilteringRule() {
super();
predicate =
CompositePredicate.withPredicate(new AvailabilityPredicate(this, null))
.addFallbackPredicate(AbstractServerPredicate.alwaysTrue())
.build();
}
@Monitor(name = "AvailableServersCount", type = DataSourceType.GAUGE)
public int getAvailableServersCount() {
ILoadBalancer lb = getLoadBalancer();
List<Server> servers = lb.getAllServers();
if (servers == null) {
return 0;
}
return Collections2.filter(servers, predicate.getServerOnlyPredicate()).size();
}
/**
* This method is overridden to provide a more efficient implementation which does not iterate
* through all servers. This is under the assumption that in most cases, there are more available
* instances than not.
*/
@Override
public Server choose(Object key) {
int count = 0;
Server server = roundRobinRule.choose(key);
while (count++ <= 10) {
if (predicate.apply(new PredicateKey(server))) {
return server;
}
server = roundRobinRule.choose(key);
}
return super.choose(key);
}
