/**
* Rebuild the point-in-time snapshot of the children objects and set watches on new
* children. @Param event may be null on the first initialization.
*/
private void processParentEvent(WatchedEvent event) throws Exception {
// get current children snapshot and reset this watch.
Set<String> children = new TreeSet<String>(m_zk.getChildren(m_rootNode, m_parentWatch));
// intersect to get newChildren and update m_lastChildren to the current set.
Set<String> newChildren = new HashSet<String>(children);
newChildren.removeAll(m_lastChildren);
m_lastChildren = children;
List<ByteArrayCallback> callbacks = new ArrayList<ByteArrayCallback>();
for (String child : children) {
ByteArrayCallback cb = new ByteArrayCallback();
// set watches on new children.
if (newChildren.contains(child)) {
m_zk.getData(ZKUtil.joinZKPath(m_rootNode, child), m_childWatch, cb, null);
} else {
m_zk.getData(ZKUtil.joinZKPath(m_rootNode, child), false, cb, null);
}
callbacks.add(cb);
}
HashMap<String, JSONObject> cache = new HashMap<String, JSONObject>();
for (ByteArrayCallback callback : callbacks) {
try {
byte payload[] = callback.getData();
JSONObject jsObj = new JSONObject(new String(payload, "UTF-8"));
cache.put(callback.getPath(), jsObj);
} catch (KeeperException.NoNodeException e) {
// child may have been deleted between the parent trigger and getData.
}
}
m_publicCache.set(ImmutableMap.copyOf(cache));
}
/** Helper to produce a valid path from variadic strings. */
public static String path(String... components) {
String path = components[0];
for (int i = 1; i < components.length; i++) {
path = ZKUtil.joinZKPath(path, components[i]);
}
return path;
}