/**
* Checks if the given {@linkplain JID} supports the requested feature. The JID may be non
* resource qualified in which case all presences belonging to that JID are checked.
*
* <p>This method does <b>not</b> perform any I/O operation and will return immediately.
*
* <p><b>Please note the return value: <code>if(isFeatureSupported(foo, bar)) ... </code> is
* likely to produce a {@link NullPointerException NPE}.</b>
*
* @param jid {@link JID} to query support for
* @param namespace the namespace of the feature
* @return <code>true</code> if the given feature is supported, <code>false</code> if it is not
* supported or <b><code>null</code> </b> if no information is available
* @see #queryFeatureSupport(JID, String, boolean)
*/
public Boolean isFeatureSupported(final JID jid, final String namespace) {
checkJID(jid);
Boolean supported = null;
final List<JID> jidsToQuery = new ArrayList<JID>();
if (jid.isBareJID()) jidsToQuery.addAll(rosterTracker.getAvailablePresences(jid));
else jidsToQuery.add(jid);
for (JID rqJID : jidsToQuery) {
DiscoverInfoWrapper info = cache.get(rqJID.toString());
if (info == null) continue;
DiscoverInfo disco = info.item;
if (disco == null) continue;
supported = disco.containsFeature(namespace);
if (supported) break;
}
return supported;
}
/**
* 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;
}
private void clearCache(Collection<String> addresses) {
for (String pjid : addresses) {
/*
* TODO We should remove all presences kept for the given
* addresses
*/
for (Presence presence : rosterTracker.getPresences(new JID(pjid))) {
clearCache(presence);
}
}
}
/**
* Returns the RQ-JID of given plain JID supporting the feature of the given name-space if
* available, otherwise null.
*
* <p>If not in the cache then a blocking cache update is performed.
*
* @param jid The JID of the user to find a supporting presence for. The JID can be resource
* qualified in which case the resource is stripped, before performing the look-up.
* @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.
*/
public JID getSupportingPresence(final JID jid, final String namespace) {
checkJID(jid);
for (Presence presence : rosterTracker.getPresences(jid.getBareJID())) {
if (!presence.isAvailable()) continue;
String rjid = presence.getFrom();
if (rjid == null) {
LOG.error("presence.getFrom() is null");
continue;
}
JID jidToCheck = new JID(rjid);
Boolean supported = queryFeatureSupport(jidToCheck, namespace);
if (supported != null && supported) return jidToCheck;
}
return null;
}
@Override
public void dispose() {
rosterTracker.removeRosterListener(rosterListener);
threadPoolExecutor.shutdownNow();
}
