private void clearCache(Presence presence) {
String rjid = presence.getFrom();
if (rjid == null) {
LOG.error("presence.getFrom() is null");
return;
}
DiscoverInfoWrapper infoWrapper = cache.remove(rjid);
if (infoWrapper != null) {
if (infoWrapper.isAvailable()) {
LOG.debug(
"clearing cache entry of contact "
+ rjid
+ ": "
+ infoWrapper.item.getChildElementXML());
} else {
LOG.debug(
"clearing cache entry of contact "
+ rjid
+ " but cache entry is empty (a discovery is "
+ "still running or the last one failed)");
}
}
}
/**
* Perform a service discovery and check if the given feature is among the features supported by
* the given recipient. All registered listeners will be notified about the result.
*
* @param jid A RQ-JID (user@host/resource) of the user to query support for or a non RQ-JID to
* query all presences for this JID.
* @blocking This method blocks until the ServiceDiscovery returns.
* @reentrant This method can be called concurrently.
* @caching If results are available in the cache, they are used instead of querying the server.
*/
private Boolean queryFeatureSupport(JID jid, String namespace) {
Boolean supported = null;
checkJID(jid);
DiscoverInfoWrapper wrapper;
final List<JID> jidsToQuery = new ArrayList<JID>();
if (jid.isBareJID()) jidsToQuery.addAll(rosterTracker.getAvailablePresences(jid));
else jidsToQuery.add(jid);
for (JID rqJID : jidsToQuery) {
// add dummy
synchronized (cache) {
wrapper = cache.get(rqJID.toString());
if (wrapper == null) {
wrapper = new DiscoverInfoWrapper();
cache.put(rqJID.toString(), wrapper);
}
}
DiscoverInfo disco = null;
// wait if there is already a discovery for the JID in progress
synchronized (wrapper) {
if (wrapper.isAvailable()) disco = wrapper.item;
else {
disco = wrapper.item = performServiceDiscovery(rqJID);
if (disco != null) LOG.debug("Inserted DiscoveryInfo into Cache for: " + rqJID);
}
}
// Null means that the discovery failed
if (disco == null) {
// and so we do not know if the feature is supported
// notifyFeatureSupportUpdated(jid, namespace, false);
continue;
}
notifyFeatureSupportUpdated(rqJID, namespace, disco.containsFeature(namespace));
/*
* loop through all presence regardless if we already know that the
* feature is supported to notify the listener for every current
* presence
*/
if (supported != null) supported |= disco.containsFeature(namespace);
else supported = disco.containsFeature(namespace);
}
return supported;
}