package org.infinispan.client.hotrod.impl.transport.tcp;
import java.net.SocketAddress;
import java.util.Arrays;
import java.util.Collection;
import java.util.Set;
import org.infinispan.client.hotrod.logging.Log;
import org.infinispan.client.hotrod.logging.LogFactory;
/**
* Round-robin implementation for {@link org.infinispan.client.hotrod.impl.transport.tcp.FailoverRequestBalancingStrategy}.
*
* @author Mircea.Markus@jboss.com
* @since 4.1
*/
public class RoundRobinBalancingStrategy implements FailoverRequestBalancingStrategy {
private static final Log log = LogFactory.getLog(RoundRobinBalancingStrategy.class);
private static final boolean trace = log.isTraceEnabled();
private int index = 0;
private SocketAddress[] servers;
@Override
public void setServers(Collection<SocketAddress> servers) {
this.servers = servers.toArray(new SocketAddress[servers.size()]);
// keep the old index if possible so that we don't produce more requests for the first server
if (index >= this.servers.length) {
index = 0;
}
if (trace) {
log.tracef("New server list is: " + Arrays.toString(this.servers));
}
}
/**
* @param failedServers Servers that should not be returned (if any other are available)
*/
@Override
public SocketAddress nextServer(Set<SocketAddress> failedServers) {
for (int i = 0;; ++i) {
SocketAddress server = getServerByIndex(index++);
// don't allow index to overflow and have a negative value
if (index >= servers.length)
index = 0;
if (failedServers == null || !failedServers.contains(server) || i >= failedServers.size()) {
if (trace) {
if (failedServers == null)
log.tracef("Selected %s from %s", server, Arrays.toString(servers));
else
log.tracef("Selected %s from %s, with failed servers %s", server, Arrays.toString(servers), failedServers.toString());
}
return server;
}
}
}
/**
* Returns same value as {@link FailoverRequestBalancingStrategy#nextServer(java.util.Set)} without modifying indexes/state.
*/
public SocketAddress dryRunNextServer() {
return getServerByIndex(index);
}
private SocketAddress getServerByIndex(int pos) {
SocketAddress server = servers[pos];
if (trace) {
log.tracef("Returning server: %s", server);
}
return server;
}
public SocketAddress[] getServers() {
return servers;
}
public int getNextPosition() {
return index;
}
}