Service Configuration and Coordination - Real-Time Analytics - page 79

public UnreliableLeader(String connect,String name) {
this .connect = connect;
this .name = name;
}
public void stateChanged(CuratorFramework arg0,
ConnectionState arg1) {
if (arg1 != ConnectionState. CONNECTED ) leader =
false ;
}
public void takeLeadership(CuratorFramework client)
throws Exception {
leader = true ;
Random rng = new Random();
while (leader) {
if (rng.nextDouble() < 0.30) {
System. out .println(name+": crashing");
return ;
}
System. out .println(name+": processing event");
Thread. sleep (rng.nextInt(1000));
}
}
}
The LeaderLatch client takes a different approach, offering a
hasLeadership method to check to see if the server still has leadership
andan await methodtowaitforleadership.Usingthe LeaderLatch looks
something like this:
LeaderLatch latch = new LeaderLatch(client,"/
leader_queue");
latch.start();
latch.await();
while(latch.hasLeadership()) {
//Do work here
}