/**
* Extracts a list of endpoint IDs from a list of {@link Endpoint}s.
*
* @param endpoints the list of {@link Endpoint}s.
* @return the list of IDs of endpoints in {@code endpoints}.
*/
private List<String> getIDs(List<Endpoint> endpoints) {
if (endpoints != null && !endpoints.isEmpty()) {
List<String> endpointIds = new LinkedList<>();
for (Endpoint endpoint : endpoints) {
endpointIds.add(endpoint.getID());
}
return endpointIds;
}
return null;
}
/**
* Notifies this instance that the ordered list of endpoints (specified as a list of endpoint IDs)
* in the conference has changed.
*
* @param endpointIds the new ordered list of endpoints (specified as a list of endpoint IDs) in
* the conference.
* @return the list of IDs of endpoints which were added to the list of forwarded endpoints as a
* result of the call.
*/
private synchronized List<String> speechActivityEndpointIdsChanged(List<String> endpointIds) {
if (conferenceSpeechActivityEndpoints.equals(endpointIds)) {
if (logger.isDebugEnabled()) {
logger.debug("Conference endpoints have not changed.");
}
return null;
} else {
List<String> newEndpoints = new LinkedList<>(endpointIds);
newEndpoints.removeAll(conferenceSpeechActivityEndpoints);
conferenceSpeechActivityEndpoints = endpointIds;
return update(newEndpoints);
}
}
/**
* Checks whether RTP packets from {@code sourceChannel} should be forwarded to {@link #channel}.
*
* @param sourceChannel the channel.
* @return {@code true} iff RTP packets from {@code sourceChannel} should be forwarded to {@link
* #channel}.
*/
public boolean isForwarded(Channel sourceChannel) {
if (lastN < 0 && currentLastN < 0) {
// If Last-N is disabled, we forward everything.
return true;
}
if (sourceChannel == null) {
logger.warn("Invalid sourceChannel: null.");
return false;
}
Endpoint channelEndpoint = sourceChannel.getEndpoint();
if (channelEndpoint == null) {
logger.warn("sourceChannel has no endpoint.");
return false;
}
if (forwardedEndpoints == INITIAL_EMPTY_LIST) {
// LastN is enabled, but we haven't yet initialized the list of
// endpoints in the conference.
initializeConferenceEndpoints();
}
// This may look like a place to optimize, because we query an unordered
// list (in O(n)) and it executes on each video packet if lastN is
// enabled. However, the size of forwardedEndpoints is restricted to
// lastN and so small enough that it is not worth optimizing.
return forwardedEndpoints.contains(channelEndpoint.getID());
}
/**
* Initializes the local list of endpoints ({@link #speechActivityEndpointsChanged(List)}) with
* the current endpoints from the conference.
*/
public synchronized void initializeConferenceEndpoints() {
speechActivityEndpointsChanged(channel.getConferenceSpeechActivity().getEndpoints());
if (logger.isDebugEnabled()) {
logger.debug(
"Initialized the list of endpoints: " + conferenceSpeechActivityEndpoints.toString());
}
}
/**
* Sets the list of "pinned" endpoints (i.e. endpoints for which video should always be forwarded,
* regardless of {@code lastN}).
*
* @param newPinnedEndpointIds the list of endpoint IDs to set.
*/
public void setPinnedEndpointIds(List<String> newPinnedEndpointIds) {
if (logger.isDebugEnabled()) {
logger.debug("Setting pinned endpoints: " + newPinnedEndpointIds.toString());
}
List<String> endpointsToAskForKeyframe = null;
synchronized (this) {
// Since we have the lock anyway, call update() inside, so it
// doesn't have to obtain it again. But keep the call to
// askForKeyframes() outside.
if (!pinnedEndpoints.equals(newPinnedEndpointIds)) {
pinnedEndpoints = Collections.unmodifiableList(newPinnedEndpointIds);
endpointsToAskForKeyframe = update();
}
}
askForKeyframes(endpointsToAskForKeyframe);
}
/**
* Notifies this instance that the ordered list of endpoints in the conference has changed.
*
* @param endpoints the new ordered list of endpoints in the conference.
* @return the list of endpoints which were added to the list of forwarded endpoints as a result
* of the call, or {@code null} if none were added.
*/
public List<Endpoint> speechActivityEndpointsChanged(List<Endpoint> endpoints) {
List<String> newEndpointIdList = getIDs(endpoints);
List<String> enteringEndpointIds = speechActivityEndpointIdsChanged(newEndpointIdList);
if (logger.isDebugEnabled()) {
logger.debug(
"New list of conference endpoints: "
+ newEndpointIdList.toString()
+ "; entering endpoints: "
+ (enteringEndpointIds == null ? "none" : enteringEndpointIds.toString()));
}
List<Endpoint> ret = new LinkedList<>();
if (enteringEndpointIds != null) {
for (Endpoint endpoint : endpoints) {
if (enteringEndpointIds.contains(endpoint.getID())) {
ret.add(endpoint);
}
}
}
return ret;
}
/**
* Sends a keyframe request to the endpoints specified in {@code endpointIds}
*
* @param endpointIds the list of IDs of endpoints to which to send a request for a keyframe.
*/
private void askForKeyframes(List<String> endpointIds) {
// TODO: Execute asynchronously.
if (endpointIds != null && !endpointIds.isEmpty()) {
channel.getContent().askForKeyframesById(endpointIds);
}
}
/**
* Recalculates the list of forwarded endpoints based on the current values of the various
* parameters of this instance ({@link #lastN}, {@link #conferenceSpeechActivityEndpoints}, {@link
* #pinnedEndpoints}).
*
* @param newConferenceEndpoints A list of endpoints which entered the conference since the last
* call to this method. They need not be asked for keyframes, because they were never filtered
* by this {@link #LastNController(VideoChannel)}.
* @return the list of IDs of endpoints which were added to {@link #forwardedEndpoints} (i.e. of
* endpoints * "entering last-n") as a result of this call. Returns {@code null} if no
* endpoints were added.
*/
private synchronized List<String> update(List<String> newConferenceEndpoints) {
List<String> newForwardedEndpoints = new LinkedList<>();
String ourEndpointId = getEndpointId();
if (conferenceSpeechActivityEndpoints == INITIAL_EMPTY_LIST) {
conferenceSpeechActivityEndpoints =
getIDs(channel.getConferenceSpeechActivity().getEndpoints());
newConferenceEndpoints = conferenceSpeechActivityEndpoints;
}
if (lastN < 0 && currentLastN < 0) {
// Last-N is disabled, we forward everything.
newForwardedEndpoints.addAll(conferenceSpeechActivityEndpoints);
if (ourEndpointId != null) {
newForwardedEndpoints.remove(ourEndpointId);
}
} else {
// Here we have lastN >= 0 || currentLastN >= 0 which implies
// currentLastN >= 0.
// Pinned endpoints are always forwarded.
newForwardedEndpoints.addAll(getPinnedEndpoints());
// As long as they are still endpoints in the conference.
newForwardedEndpoints.retainAll(conferenceSpeechActivityEndpoints);
if (newForwardedEndpoints.size() > currentLastN) {
// What do we want in this case? It looks like a contradictory
// request from the client, but maybe it makes for a good API
// on the client to allow the pinned to override last-n.
// Unfortunately, this will not play well with Adaptive-Last-N
// or changes to Last-N for other reasons.
} else if (newForwardedEndpoints.size() < currentLastN) {
for (String endpointId : conferenceSpeechActivityEndpoints) {
if (newForwardedEndpoints.size() < currentLastN) {
if (!endpointId.equals(ourEndpointId) && !newForwardedEndpoints.contains(endpointId)) {
newForwardedEndpoints.add(endpointId);
}
} else {
break;
}
}
}
}
List<String> enteringEndpoints;
if (forwardedEndpoints.equals(newForwardedEndpoints)) {
// We want forwardedEndpoints != INITIAL_EMPTY_LIST
forwardedEndpoints = newForwardedEndpoints;
enteringEndpoints = null;
} else {
enteringEndpoints = new ArrayList<>(newForwardedEndpoints);
enteringEndpoints.removeAll(forwardedEndpoints);
if (logger.isDebugEnabled()) {
logger.debug(
"Forwarded endpoints changed: "
+ forwardedEndpoints.toString()
+ " -> "
+ newForwardedEndpoints.toString()
+ ". Entering: "
+ enteringEndpoints.toString());
}
forwardedEndpoints = Collections.unmodifiableList(newForwardedEndpoints);
if (lastN >= 0 || currentLastN >= 0) {
// TODO: we may want to do this asynchronously.
channel.sendLastNEndpointsChangeEventOnDataChannel(forwardedEndpoints, enteringEndpoints);
}
}
// If lastN is disabled, the endpoints entering forwardedEndpoints were
// never filtered, so they don't need to be asked for keyframes.
if (lastN < 0 && currentLastN < 0) {
enteringEndpoints = null;
}
if (enteringEndpoints != null && newConferenceEndpoints != null) {
// Endpoints just entering the conference need not be asked for
// keyframes.
enteringEndpoints.removeAll(newConferenceEndpoints);
}
return enteringEndpoints;
}
/** @return the number of streams currently being forwarded. */
public int getN() {
return forwardedEndpoints.size();
}