private <C extends Command<R>, R extends Serializable> void registerExecutor(
final NodeContext nodeContext, final CommandExecutor<C, R> executor, ZNode node) {
final ZNode executorNode =
node.createChild(znode().withPath(nodeNameOf(executor.getQualifier())));
final ZNode queueNode = executorNode.createChild(znode().withPath("queue"));
executorNode.createChild(znode().withPath("result"));
log.debug("Created znodes for executor {}", executorNode.getPath());
queueNode.addChildrenWatcher(
new Watcher() {
@Override
public void process(WatchedEvent event) {
if (event.getType() != Event.EventType.NodeChildrenChanged) {
return;
}
synchronized (lock) {
if (log.isDebugEnabled()) {
log.debug(
"Children changed {} event type {}", queueNode.getPath(), event.getType());
}
List<QueueEntry<C, R>> entries = getEntries(queueNode, this);
for (final QueueEntry<C, R> entry : entries) {
Runnable run =
new Runnable() {
@Override
public void run() {
executeCommand(executor, executorNode, entry, nodeContext);
}
};
ZookeeperCoordinator.this.executor.execute(run);
}
}
}
});
}
private static <C extends Command<R>, R extends Serializable> void executeCommand(
CommandExecutor<C, R> executor,
ZNode executorNode,
final QueueEntry<C, R> entry,
final NodeContext nodeContext) {
String relativePath = entry.getResultPath().substring(executorNode.getPath().length() + 1);
final ZNode output = executorNode.child(relativePath);
final NodeCommandExecutionListener<C> listener = entry.getListener();
try {
C command = entry.getCommand();
listener.onCommandExecutionStarted(command, nodeContext);
R result = executor.execute(command, nodeContext);
log.debug("Command {} executed", command);
listener.onCommandExecuted(command);
output.setObject(CommandExecutionResult.success(result));
} catch (Throwable throwable) {
// todo add fail event
log.error("error during task execution", throwable);
output.setObject(CommandExecutionResult.fail(throwable));
}
}