private void handleStateChange(ConnectionState newState) {
switch (newState) {
default:
{
// NOP
break;
}
case RECONNECTED:
{
try {
reset();
} catch (Exception e) {
log.error("Could not reset leader latch", e);
setLeadership(false);
}
break;
}
case SUSPENDED:
case LOST:
{
setLeadership(false);
break;
}
}
}
/**
* Add this instance to the leadership election and attempt to acquire leadership.
*
* @throws Exception errors
*/
public void start() throws Exception {
Preconditions.checkState(
state.compareAndSet(State.LATENT, State.STARTED), "Cannot be started more than once");
client.getConnectionStateListenable().addListener(listener);
reset();
}
private void checkLeadership(List<String> children) throws Exception {
final String localOurPath = ourPath.get();
List<String> sortedChildren = LockInternals.getSortedChildren(LOCK_NAME, sorter, children);
int ourIndex =
(localOurPath != null) ? sortedChildren.indexOf(ZKPaths.getNodeFromPath(localOurPath)) : -1;
if (ourIndex < 0) {
log.error("Can't find our node. Resetting. Index: " + ourIndex);
reset();
} else if (ourIndex == 0) {
setLeadership(true);
} else {
String watchPath = sortedChildren.get(ourIndex - 1);
Watcher watcher =
new Watcher() {
@Override
public void process(WatchedEvent event) {
if ((state.get() == State.STARTED)
&& (event.getType() == Event.EventType.NodeDeleted)
&& (localOurPath != null)) {
try {
getChildren();
} catch (Exception ex) {
log.error("An error occurred checking the leadership.", ex);
}
}
}
};
BackgroundCallback callback =
new BackgroundCallback() {
@Override
public void processResult(CuratorFramework client, CuratorEvent event)
throws Exception {
if (event.getResultCode() == KeeperException.Code.NONODE.intValue()) {
// previous node is gone - reset
reset();
}
}
};
client
.checkExists()
.usingWatcher(watcher)
.inBackground(callback)
.forPath(ZKPaths.makePath(latchPath, watchPath));
}
}
