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package derms.net.rmulticast;
import derms.io.Serial;
import derms.util.Wait;
import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.ClosedChannelException;
import java.nio.channels.DatagramChannel;
import java.time.Duration;
import java.util.Set;
import java.util.logging.Logger;
/**
* Periodically send acknowledgements to the group. Allows acks to propagate even when some
* processes wouldn't normally send messages. Also allows processes to populate their set of
* group members.
*/
class Heartbeat implements Runnable {
private static final Duration period = Duration.ofSeconds(30);
private final InetSocketAddress group;
private final InetAddress laddr;
private final Set<MessageID> acks, nacks;
private final DatagramChannel sock;
private final Logger log;
Heartbeat(InetSocketAddress group, InetAddress laddr, Set<MessageID> acks, Set<MessageID> nacks, DatagramChannel sock) throws IOException {
this.group = group;
this.laddr = laddr;
this.acks = acks;
this.nacks = nacks;
this.sock = sock;
this.log = Logger.getLogger(this.getClass().getName());
}
@Override
public void run() {
for (;;) {
try {
Wait.forDuration(period);
send();
} catch (InterruptedException | ClosedChannelException e) {
log.info("Shutting down.");
return;
} catch (IOException e) {
log.warning(e.getMessage());
}
}
}
private void send() throws IOException {
HeartbeatMessage msg = new HeartbeatMessage(
laddr,
acks.toArray(new MessageID[0]),
nacks.toArray(new MessageID[0]));
ByteBuffer buf = Serial.encode(msg);
sock.send(buf, group);
acks.clear();
}
}
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