Moving to @users...
There's not enough of a code snippet to answer properly. However, I'd use a
LeaderSelector instead and allocate/use the PathChildrenCache inside of it.
-Jordan
> On Dec 21, 2017, at 5:12 AM, 習慣/zt①个 <381954...@qq.com> wrote:
>
> Hello:
> I'd like to launch a APP which replicas is 2. These two same APPs used
> 'PathChildrenCache' to watch a ZK path.
> I expect that the only one app(the leader) execute the
> 'PathChildrenCacheListener' event. Do i need to wait the leader elect
> completely
> before executing 'PathChildrenCacheListener' event ?
> I worry that node changing trigger 'PathChildrenCacheListener' event
> before electing leader completely, especially in unstable network.
>
> [demo]:
> PathChildrenCache cache = new PathChildrenCache(client, nodePath, false);
> cache.getListenable().addListener(new PathChildrenCacheListener() {
> @Override
> public void childEvent(CuratorFramework client, PathChildrenCacheEvent
> event) throws Exception {
> if (event.getType() == Type.CHILD_ADDED
> || event.getType() == Type.CHILD_REMOVED) {
>
> // wait leader elect completely
> while (!leaderLatch.getLeader().isLeader()) {
> try {
> TimeUnit.MILLISECONDS.sleep(1000);
> } catch (InterruptedException e) {
> Thread.currentThread().interrupt();
> }
> }
>
> String node = ZKPaths.getNodeFromPath(event.getData().getPath());
> if (leaderLatch.hasLeadership()) {
> switch (event.getType()) {
> case CHILD_ADDED:
> log.info("Added node : {}", node);
> // TODO: 2017/12/21
> break;
> case CHILD_REMOVED:
> log.info("Removed node : {}", node);
> // TODO: 2017/12/21
> break;
> }
> } else {
> log.info("This LeaderLatch is not leader");
> }
> }
> }
> });
> cache.start();
>
