That’s essentially what I was suggesting. But, you’d need to keep track of all the created PathChildrenCache objects in a map or something so that you can delete/close them when needed. Also, use a common executor service to avoid thread pool explosion.
-JZ From: Check Peck Check Peck Reply: Check Peck [email protected] Date: February 9, 2014 at 10:10:26 PM To: Jordan Zimmerman [email protected] Subject: Re: How to watch on descendant znodes using Curator PathCache? What about for now, If I keep on recursively using PathChildrenCache for making a watches on each children's? private static void addListener(PathChildrenCache cache) { PathChildrenCacheListener listener = new PathChildrenCacheListener() { public void childEvent(CuratorFramework client, PathChildrenCacheEvent event) throws Exception { switch (event.getType()) { case CHILD_ADDED: { String path = ZKPaths.getPathAndNode(event.getData().getPath()).getPath(); String node = ZKPaths.getNodeFromPath(event.getData().getPath()); System.out.println("Node added: " + path + " " + node); // recursively keep on creating watches PathChildrenCache cache = new PathChildrenCache(client, path + "/" + node, true); cache.start(); addListener(cache); break; } } } } } Will there be any problem if I do it like this? On Sun, Feb 9, 2014 at 6:53 PM, Jordan Zimmerman <[email protected]> wrote: If I were to do something like this I’d use a Guava Cache or something to hold PathChildrenCache objects for each child node. That’s a quick’n’dirty solution. I think you’d want to pass in a common CloseableExecutorService to avoid too many threads. This might get cumbersome to manage though. If you only need the one sub-level, you could use NodeCache for each of the children instead of PathChildrenCache. Whenever the PathChildrenCache sends a CHILD_ADDED, you allocate a new PatchChildrenCache/NodeCache for that node. When CHILD_REMOVED is sent, close and remove it. So, what you end with is a map of PatchChildrenCache/NodeCache instances. So, this is off the top of my head and I haven’t thought through all the edge cases. If it works, though, it might make a nice recipe addition. -JZ From: Check Peck Check Peck Reply: Check Peck [email protected] Date: February 9, 2014 at 9:35:24 PM To: Jordan Zimmerman [email protected] Subject: Re: How to watch on descendant znodes using Curator PathCache? Thanks for suggestion. I am using PathChildrenCache for one level. For example - If my root node is - "/my/test" and I am keeping a watch on that node using the PathChildrenCache as mentioned in my previous email code. So suppose if these nodes gets added to my root node - "/my/test/test1" "/my/test/test2" "/my/test/test3" Then I get notified and it works fine with the PathChildrenCache code but if any new node gets added, updated or removed to `"/my/test/test1"`, `"/my/test/test2"` and `"/my/test/test3"` then it doesn't works and no watches gets triggered and I am not able to understand how to make that work as my understanding is very limited as of now. On Sun, Feb 9, 2014 at 6:31 PM, Jordan Zimmerman <[email protected]> wrote: Do you need just the one level? If so, why not use PathChildrenCache: http://curator.apache.org/curator-recipes/path-cache.html -JZ From: Check Peck Check Peck Reply: [email protected] [email protected] Date: February 9, 2014 at 9:08:20 PM To: user [email protected] Subject: How to watch on descendant znodes using Curator PathCache? I am working on a project in which I need to maintain a watches on a node, and that nodes children as well. I have tried using PathCache but I am not sure how to watch for childrens children here? Here my root node is - `"/my/test"` and I am keeping a watch on that node using the below code. What I want to do is, to keep the watch on `"/my/test"` znode. So suppose if these nodes gets added to my root node - "/my/test/test1" "/my/test/test2" "/my/test/test3" Then I should get notified (till this part I am able to make it work) but if any new node gets added, updated or removed to `"/my/test/test1"`, `"/my/test/test2"` and `"/my/test/test3"` then I should also get notified and this is the part I am not able to understand how to make it work. Whenever I am adding any new node to `"/my/test"` such as `"/my/test/test1"`, `"/my/test/test2"`, `"/my/test/test3"` then the watch gets triggered with the use of below code. But if I am adding any new node to `"/my/test/test1"` or `"/my/test/test2"`, then no watches get triggerd and I am not sure how to add the code for that as well? Any thoughts how this can be done? May be if somebody has done this in the past.. So any example will be of great help to me.. Below is my code which works fine for `"/my/test"` children but not the childrens of `"/my/test/test1"` and etc etc. private static final String PATH = "/my/test"; public static void main(String[] args) { CuratorFramework client = null; PathChildrenCache cache = null; try { client = CuratorClient.createSimple("localhost:2181"); client.start(); // in this example we will cache data. Notice that this is optional. cache = new PathChildrenCache(client, PATH, true); cache.start(); addListener(cache); for(;;) { try { Thread.sleep(50000); } catch(InterruptedException e) { } } } catch (Exception e1) { e1.printStackTrace(); } } Below is my addListener method - private static void addListener(PathChildrenCache cache) { PathChildrenCacheListener listener = new PathChildrenCacheListener() { public void childEvent(CuratorFramework client, PathChildrenCacheEvent event) throws Exception { switch (event.getType()) { case CHILD_ADDED: { System.out.println("Node added: " + ZKPaths.getNodeFromPath(event.getData().getPath())); break; } case CHILD_UPDATED: { System.out.println("Node changed: " + ZKPaths.getNodeFromPath(event.getData().getPath())); break; } case CHILD_REMOVED: { System.out.println("Node removed: " + ZKPaths.getNodeFromPath(event.getData().getPath())); break; } default: break; } } }; cache.getListenable().addListener(listener); } Can anyone provide a simple example for this for my use case? I am using Curator 2.4.0 which got released recently.
