@Override
public void run() {
if (isSynchronizedWithZooKeeper.get() || !zkClient.isConnected() || !started.get()) {
return;
}
if (checkVersion.getAndSet(false)) {
try {
synchronized (lastStatusVersionMonitor) {
final Stat stat = zkClient.getZookeeper().exists(path, null);
if (stat != null
&& zkClient.getZookeeper().getSessionId() == stat.getEphemeralOwner()) {
zkClient.getZookeeper().delete(path, lastStatusVersion);
}
}
} catch (InterruptedException e) {
LOG.info("Interrupted");
checkVersion.set(true);
} catch (KeeperException e) {
LOG.info("exception " + e.getMessage());
checkVersion.set(true);
}
}
LOG.info(
"We are out-of-sync, have a zookeeper connection, and are started, trying reclaim: "
+ path
+ this);
tryClaim();
}
@Override
public void processResult(int rawReturnCode, String notUsed, Object parent, String notUsed2) {
KeeperException.Code returnCode = KeeperException.Code.get(rawReturnCode);
ClaimedCoordinate claimedCoordinate = (ClaimedCoordinate) parent;
LOG.fine(
"Claim callback with "
+ returnCode.name()
+ " "
+ claimedCoordinate.path
+ " synched: "
+ isSynchronizedWithZooKeeper.get()
+ " thread: "
+ this);
switch (returnCode) {
// The claim was successful. This means that the node was created. We need to
// populate the status and endpoints.
case OK:
// We should be the first one to write to the new node, or fail.
// This requires that the first version is 0, have not seen this documented
// but it should be a fair assumption and is verified by unit tests.
synchronized (lastStatusVersionMonitor) {
lastStatusVersion = 0;
}
// We need to set this to synced or updateCoordinateData will complain.
// updateCoordinateData will set it to out-of-sync in case of problems.
isSynchronizedWithZooKeeper.set(true);
try {
registerWatcher();
} catch (CloudnameException e) {
LOG.fine(
"Failed register watcher after claim. Going to state out of sync: "
+ e.getMessage());
isSynchronizedWithZooKeeper.set(false);
return;
} catch (InterruptedException e) {
LOG.fine("Interrupted while setting up new watcher. Going to state out of sync.");
isSynchronizedWithZooKeeper.set(false);
return;
}
// No exceptions, let's celebrate with a log message.
LOG.info("Claim processed ok, path: " + path);
claimedCoordinate.sendEventToCoordinateListener(
CoordinateListener.Event.COORDINATE_OK, "claimed");
return;
case NODEEXISTS:
// Someone has already claimed the coordinate. It might have been us in a
// different thread. If we already have claimed the coordinate then don't care.
// Else notify the client. If everything is fine, this is not a true negative,
// so ignore it. It might happen if two attempts to tryClaim the coordinate run
// in parallel.
if (isSynchronizedWithZooKeeper.get() && started.get()) {
LOG.fine("Everything is fine, ignoring NODEEXISTS message, path: " + path);
return;
}
LOG.info("Claimed fail, node already exists, will retry: " + path);
claimedCoordinate.sendEventToCoordinateListener(
CoordinateListener.Event.NOT_OWNER, "Node already exists.");
LOG.info("isSynchronizedWithZooKeeper: " + isSynchronizedWithZooKeeper.get());
checkVersion.set(true);
return;
case NONODE:
LOG.info("Could not claim due to missing coordinate, path: " + path);
claimedCoordinate.sendEventToCoordinateListener(
CoordinateListener.Event.NOT_OWNER,
"No node on claiming coordinate: " + returnCode.name());
return;
default:
// Random problem, report the problem to the client.
claimedCoordinate.sendEventToCoordinateListener(
CoordinateListener.Event.NO_CONNECTION_TO_STORAGE,
"Could not reclaim coordinate. Return code: " + returnCode.name());
return;
}
}