org.cometd.oort.Seti Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2021 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.cometd.oort;
import java.io.IOException;
import java.util.AbstractMap;
import java.util.Collection;
import java.util.Collections;
import java.util.EventListener;
import java.util.EventObject;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import java.util.TreeMap;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.stream.Collectors;
import org.cometd.bayeux.Message;
import org.cometd.bayeux.Promise;
import org.cometd.bayeux.client.ClientSessionChannel;
import org.cometd.bayeux.server.BayeuxServer;
import org.cometd.bayeux.server.LocalSession;
import org.cometd.bayeux.server.SecurityPolicy;
import org.cometd.bayeux.server.ServerChannel;
import org.cometd.bayeux.server.ServerMessage;
import org.cometd.bayeux.server.ServerSession;
import org.cometd.server.AbstractService;
import org.cometd.server.BayeuxServerImpl;
import org.eclipse.jetty.util.annotation.ManagedAttribute;
import org.eclipse.jetty.util.annotation.ManagedObject;
import org.eclipse.jetty.util.annotation.ManagedOperation;
import org.eclipse.jetty.util.annotation.Name;
import org.eclipse.jetty.util.component.AbstractLifeCycle;
import org.eclipse.jetty.util.component.Dumpable;
import org.eclipse.jetty.util.component.DumpableCollection;
import org.eclipse.jetty.util.thread.AutoLock;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* The component that Searches for Extra Terrestrial Intelligence or,
* in this case, just searches for a user logged onto a comet in an Oort cloud.
* Seti allows an application to maintain a mapping from userId (any application
* identifier such as user names or database IDs that represent users) to
* server sessions using the {@link #associate(String, ServerSession)} and
* {@link #disassociate(String, ServerSession)} methods.
* A typical example of usage of {@link Seti#associate(String, ServerSession)} is
* in a {@link SecurityPolicy} after a successful handshake (where authentication
* information can be linked with the server session), or in {@link AbstractService CometD services}
* where the association is established upon receiving a message on a particular channel
* processed by the service itself.
* Each comet in the cluster keeps its own mapping for clients connected to it.
* The {@link #sendMessage(Collection, String, Object)} and
* {@link #sendMessage(String, String, Object)} methods may be
* used to send messages to user(s) anywhere in the Oort cluster
* and Seti organizes the search in order to locate the user(s).
*
* @see SetiServlet
*/
@ManagedObject("CometD cloud peer discovery component")
public class Seti extends AbstractLifeCycle implements Dumpable {
public static final String SETI_ATTRIBUTE = Seti.class.getName();
private static final String SETI_ALL_CHANNEL = "/seti/all";
private final AutoLock lock = new AutoLock();
private final Map> _uid2Location = new HashMap<>();
private final List _presenceListeners = new CopyOnWriteArrayList<>();
private final Oort.CometListener _cometListener = new CometListener();
private final ServerChannel.SubscriptionListener _initialStateListener = new InitialStateListener();
private final Oort _oort;
private final String _setiId;
private final Logger _logger;
private final LocalSession _session;
public Seti(Oort oort) {
_oort = oort;
_setiId = generateSetiId(oort.getURL());
_logger = LoggerFactory.getLogger(getClass().getName() + "." + _setiId);
_session = oort.getBayeuxServer().newLocalSession(_setiId);
}
@ManagedAttribute(value = "The Oort of this Seti", readonly = true)
public Oort getOort() {
return _oort;
}
@ManagedAttribute(value = "The unique ID of this Seti", readonly = true)
public String getId() {
return _setiId;
}
@Override
protected void doStart() {
BayeuxServer bayeux = _oort.getBayeuxServer();
_session.handshake();
ServerChannel setiAllChannel = bayeux.createChannelIfAbsent(SETI_ALL_CHANNEL).getReference();
setiAllChannel.addListener(_initialStateListener);
_session.getChannel(SETI_ALL_CHANNEL).subscribe((channel, message) -> receiveBroadcast(message));
_oort.observeChannel(SETI_ALL_CHANNEL);
String setiChannelName = generateSetiChannel(_setiId);
_session.getChannel(setiChannelName).subscribe((channel, message) -> receiveDirect(message));
_oort.observeChannel(setiChannelName);
_oort.addCometListener(_cometListener);
if (_logger.isDebugEnabled()) {
_logger.debug("{} started", this);
}
}
@Override
protected void doStop() {
removeAssociationsAndPresences();
_presenceListeners.clear();
_session.disconnect();
_oort.removeCometListener(_cometListener);
String setiChannelName = generateSetiChannel(_setiId);
_oort.deobserveChannel(setiChannelName);
_oort.deobserveChannel(SETI_ALL_CHANNEL);
ServerChannel setiAllChannel = _oort.getBayeuxServer().getChannel(SETI_ALL_CHANNEL);
if (setiAllChannel != null) {
setiAllChannel.removeListener(_initialStateListener);
}
}
protected String generateSetiId(String oortURL) {
return Oort.replacePunctuation(oortURL, '_');
}
protected String generateSetiChannel(String setiId) {
return "/seti/" + setiId;
}
/**
* Associates the given userId to the given session.
* If it is the first association for this userId, broadcasts this information
* on the Oort cloud, so that other comets will know that the given userId is on this comet.
*
* @param userId the user identifier to associate
* @param session the session to map the userId to
* @return true if the session has been associated, false if it was already associated
* @see #isAssociated(String)
* @see #disassociate(String, ServerSession)
*/
public boolean associate(String userId, ServerSession session) {
if (session == null) {
throw new NullPointerException();
}
LocalLocation location = new LocalLocation(userId, session);
boolean wasAssociated = isAssociated(userId);
boolean added = associate(userId, location);
if (added) {
if (_logger.isDebugEnabled()) {
_logger.debug("Associated session {} to user {}", session, userId);
}
session.addListener(location);
session.setAttribute(LocalLocation.class.getName(), location);
if (!wasAssociated) {
if (_logger.isDebugEnabled()) {
_logger.debug("Broadcasting association addition for user {}", userId);
}
// Let everyone in the cluster know that this session is here
_session.getChannel(SETI_ALL_CHANNEL).publish(new SetiPresence(true, userId));
}
}
return added;
}
protected boolean associate(String userId, Location location) {
if (!isRunning()) {
return false;
}
try (AutoLock l = lock.lock()) {
Set locations = _uid2Location.computeIfAbsent(userId, k -> new HashSet<>());
boolean result = locations.add(location);
if (_logger.isDebugEnabled()) {
_logger.debug("Associations: {}", _uid2Location.size());
}
// Logging below can generate hugely long lines.
if (_logger.isTraceEnabled()) {
_logger.trace("Associations: {}", _uid2Location);
}
return result;
}
}
private boolean associateRemote(String userId, SetiLocation location) {
// There is a possibility that a remote Seti sends an association,
// but immediately afterwards crashes.
// This Seti may process the crash _before_ the association, leaving
// this Seti with an association to a crashed Seti.
// Here we check if, after the association, the other node is
// still connected. If not, we disassociate. If so, and the other
// node crashes just afterwards, the "comet left" event will take
// care of disassociating the remote users.
boolean associated = associate(userId, location);
String oortURL = location._oortURL;
if (associated && !_oort.isCometConnected(oortURL)) {
if (_logger.isDebugEnabled()) {
_logger.debug("Disassociating {} since comet {} is not connected", userId, oortURL);
}
disassociate(userId, location);
return false;
}
return associated;
}
/**
* @param userId the user identifier to test for association
* @return whether the given userId has been associated via {@link #associate(String, ServerSession)}
* @see #associate(String, ServerSession)
* @see #isPresent(String)
* @see #getAssociationCount(String)
*/
@ManagedOperation(value = "Whether the given userId is associated locally", impact = "INFO")
public boolean isAssociated(@Name(value = "userId", description = "The userId to test for local association") String userId) {
try (AutoLock l = lock.lock()) {
Set locations = _uid2Location.get(userId);
if (locations == null) {
return false;
}
for (Location location : locations) {
if (location instanceof LocalLocation) {
return true;
}
}
return false;
}
}
/**
* @param userId the user identifier to test for association count
* @return the number of local associations
* @see #isAssociated(String)
* @see #getPresenceCount(String)
*/
@ManagedOperation(value = "The number of local associations for the given userId", impact = "INFO")
public int getAssociationCount(@Name(value = "userId", description = "The userId to test for local association count") String userId) {
try (AutoLock l = lock.lock()) {
Set locations = _uid2Location.get(userId);
if (locations == null) {
return 0;
}
int result = 0;
for (Location location : locations) {
if (location instanceof LocalLocation) {
++result;
}
}
return result;
}
}
/**
* @param userId the user identifier to test for presence
* @return whether the given userId is present on the cloud (and therefore has been associated
* either locally or remotely)
* @see #isAssociated(String)
* @see #getPresenceCount(String)
*/
@ManagedOperation(value = "Whether the given userId is present in the cloud", impact = "INFO")
public boolean isPresent(@Name(value = "userId", description = "The userId to test for presence in the cloud") String userId) {
try (AutoLock l = lock.lock()) {
Set locations = _uid2Location.get(userId);
return locations != null;
}
}
/**
* @param userId the user identifier to test for presence count
* @return the number of associations (local or remote) on the cloud
* @see #isPresent(String)
* @see #getAssociationCount(String)
*/
@ManagedOperation(value = "The number of local and remote associations for the given userId", impact = "INFO")
public int getPresenceCount(@Name(value = "userId", description = "The userId to test for presence count") String userId) {
try (AutoLock l = lock.lock()) {
Set locations = _uid2Location.get(userId);
return locations == null ? 0 : locations.size();
}
}
/**
* Disassociates the given userId from the given session.
* If this is the last disassociation for this userId, broadcasts this information
* on the Oort cloud, so that other comets will know that the given userId no longer is on this comet.
*
* @param userId the user identifier to disassociate
* @param session the session mapped to the userId
* @return true if the session has been disassociated, false if it was not associated
* @see #associate(String, ServerSession)
*/
public boolean disassociate(String userId, ServerSession session) {
LocalLocation location = new LocalLocation(userId, session);
boolean removed = disassociate(userId, location);
if (removed) {
if (_logger.isDebugEnabled()) {
_logger.debug("Disassociated session {} from user {}", session, userId);
}
location = (LocalLocation)session.removeAttribute(LocalLocation.class.getName());
session.removeListener(location);
// Seti is stopped before BayeuxServer, but it may happen that RemoveListeners
// call Seti when BayeuxServer is stopping, and they will find that Seti is already stopped.
// Do not do any action in this case, because exceptions are thrown if the action is
// attempted (as _session is already disconnected).
// Also, we only broadcast the presence message if no associations are left for the user,
// because remote comets are not aware of multiple associations.
// Consider the case where the same user is associated twice to a comet, and then only
// one association is disassociated. The other comets do not know that the comet had multiple
// associations, and if a presence message is sent, the remote comets will wrongly think
// that the user is gone, while in reality it is still associated with the remaining association.
if (_session.isConnected() && !isAssociated(userId)) {
if (_logger.isDebugEnabled()) {
_logger.debug("Broadcasting association removal for user {}", userId);
}
// Let everyone in the cluster know that this session is not here anymore
_session.getChannel(SETI_ALL_CHANNEL).publish(new SetiPresence(false, userId));
}
}
return removed;
}
/**
* Disassociates the given userId from all sessions.
* If this user had sessions on this comet, broadcast this information
* on the Oort cloud, so that other comets will know that the given userId no longer is on this comet.
*
* @param userId the user identifier to disassociate
* @return set of sessions that were disassociated
* @see #associate(String, ServerSession)
*/
public Set disassociate(String userId) {
Set localLocations = new HashSet<>();
try (AutoLock l = lock.lock()) {
Set userLocations = _uid2Location.get(userId);
if (userLocations != null) {
for (Location location : userLocations) {
if (location instanceof LocalLocation) {
localLocations.add((LocalLocation)location);
}
}
}
}
Set removedUserSessions = new HashSet<>();
for (LocalLocation location : localLocations) {
ServerSession session = location._session;
boolean removed = disassociate(userId, session);
if (removed) {
removedUserSessions.add(session);
}
}
return removedUserSessions;
}
protected boolean disassociate(String userId, Location location) {
try (AutoLock l = lock.lock()) {
boolean result = false;
Set locations = _uid2Location.get(userId);
if (locations != null) {
result = locations.remove(location);
if (locations.isEmpty()) {
_uid2Location.remove(userId);
}
}
if (_logger.isDebugEnabled()) {
_logger.debug("Associations: {}", _uid2Location.size());
}
// Logging below can generate hugely long lines.
if (_logger.isTraceEnabled()) {
_logger.trace("Associations: {}", _uid2Location);
}
return result;
}
}
protected void removeAssociationsAndPresences() {
Set userIds = new HashSet<>();
try (AutoLock l = lock.lock()) {
getAssociatedUserIds(userIds);
_uid2Location.clear();
}
if (_logger.isDebugEnabled()) {
_logger.debug("Broadcasting association removal for users {}", userIds);
}
SetiPresence presence = new SetiPresence(Collections.emptySet());
presence.put(SetiPresence.ALIVE_FIELD, false);
_session.getChannel(SETI_ALL_CHANNEL).publish(presence);
}
protected void removePresences(String oortURL) {
Set userIds = removeRemotePresences(oortURL);
if (_logger.isDebugEnabled()) {
_logger.debug("Removing presences of comet {} for users {}", oortURL, userIds);
}
for (String userId : userIds) {
notifyPresenceRemoved(oortURL, userId);
}
}
private Set removeRemotePresences(String oortURL) {
Set userIds = new HashSet<>();
try (AutoLock l = lock.lock()) {
Iterator>> entries = _uid2Location.entrySet().iterator();
while (entries.hasNext()) {
Map.Entry> entry = entries.next();
Set userLocations = entry.getValue();
Iterator iterator = userLocations.iterator();
while (iterator.hasNext()) {
Location location = iterator.next();
if (location instanceof SetiLocation) {
if (oortURL.equals(((SetiLocation)location)._oortURL)) {
iterator.remove();
userIds.add(entry.getKey());
break;
}
}
}
if (userLocations.isEmpty()) {
entries.remove();
}
}
}
return userIds;
}
/**
* @return the set of {@code userId}s known to this Seti, both local and remote
*/
@ManagedAttribute(value = "The set of userIds known to this Seti", readonly = true)
public Set getUserIds() {
try (AutoLock l = lock.lock()) {
return new HashSet<>(_uid2Location.keySet());
}
}
/**
* @return the set of {@code userId}s associated via {@link #associate(String, ServerSession)}
*/
public Set getAssociatedUserIds() {
Set result = new HashSet<>();
getAssociatedUserIds(result);
return result;
}
private void getAssociatedUserIds(Set result) {
try (AutoLock l = lock.lock()) {
for (Map.Entry> entry : _uid2Location.entrySet()) {
for (Location location : entry.getValue()) {
if (location instanceof LocalLocation) {
result.add(entry.getKey());
break;
}
}
}
}
}
/**
* Sends a message to the given userId in the Oort cloud.
*
* @param toUserId the userId to send the message to
* @param toChannel the channel to send the message to
* @param data the content of the message
* @see #sendMessage(Collection, String, Object)
*/
public void sendMessage(String toUserId, String toChannel, Object data) {
sendMessage(Set.of(toUserId), toChannel, data);
}
/**
* Sends a message to multiple userIds in the Oort cloud.
*
* @param toUserIds the userIds to send the message to
* @param toChannel the channel to send the message to
* @param data the content of the message
*/
public void sendMessage(Collection toUserIds, String toChannel, Object data) {
for (String toUserId : toUserIds) {
Set copy = new HashSet<>();
try (AutoLock l = lock.lock()) {
Set locations = _uid2Location.get(toUserId);
if (locations == null) {
copy.add(new SetiLocation(toUserId, null));
} else {
copy.addAll(locations);
}
}
if (_logger.isDebugEnabled()) {
_logger.debug("Sending message to locations {}", copy);
}
for (Location location : copy) {
location.send(toUserId, toChannel, data);
}
}
}
/**
* Receives messages directly from other Setis in the cloud, containing
* messages to be delivered to sessions connected to this comet.
*
* @param message the message to deliver to a session connected to this comet
*/
protected void receiveDirect(Message message) {
if (_logger.isDebugEnabled()) {
_logger.debug("Received direct message {}", message);
}
Map data = message.getDataAsMap();
Boolean presence = (Boolean)data.get(SetiPresence.PRESENCE_FIELD);
if (presence != null) {
receivePresence(data);
} else {
receiveMessage(data);
}
}
/**
* Receives messages broadcast by other Setis in the cloud.
* Broadcast messages may be presence messages, where another Seti advertises
* an association, or fallback messages.
* Fallback messages are messages that were sent to a particular Seti because the
* sender thought the target userId was there, but the receiving Seti does not know
* that userId anymore (for example, it just disconnected); in this case, the receiving
* Seti broadcasts the message to the whole cloud, in the hope that the user can be
* found in some other comet of the cloud.
*
* @param message the message to possibly deliver to a session connected to this comet
*/
protected void receiveBroadcast(Message message) {
if (_logger.isDebugEnabled()) {
_logger.debug("Received broadcast message {}", message);
}
Map data = message.getDataAsMap();
Boolean presence = (Boolean)data.get(SetiPresence.PRESENCE_FIELD);
if (presence != null) {
receivePresence(data);
} else {
receiveMessage(data);
}
}
/**
* Receives a presence message.
*
* @param presence the presence message received
*/
protected void receivePresence(Map presence) {
if (_logger.isDebugEnabled()) {
_logger.debug("Received presence message {}", presence);
}
String oortURL = (String)presence.get(SetiPresence.OORT_URL_FIELD);
if (_setiId.equals(generateSetiId(oortURL))) {
receiveLocalPresence(presence);
} else {
receiveRemotePresence(presence);
}
}
protected void receiveLocalPresence(Map presence) {
String oortURL = (String)presence.get(SetiPresence.OORT_URL_FIELD);
boolean present = (Boolean)presence.get(SetiPresence.PRESENCE_FIELD);
Set userIds = convertPresenceUsers(presence);
if (_logger.isDebugEnabled()) {
_logger.debug("Notifying presence listeners {}", presence);
}
for (String userId : userIds) {
if (present) {
notifyPresenceAdded(oortURL, userId);
} else {
notifyPresenceRemoved(oortURL, userId);
}
}
}
protected void receiveRemotePresence(Map presence) {
String oortURL = (String)presence.get(SetiPresence.OORT_URL_FIELD);
boolean present = (Boolean)presence.get(SetiPresence.PRESENCE_FIELD);
boolean replace = presence.get(SetiPresence.REPLACE_FIELD) == Boolean.TRUE;
Set userIds = convertPresenceUsers(presence);
if (_logger.isDebugEnabled()) {
_logger.debug("Received remote presence message from comet {} for {}", oortURL, userIds);
}
Set added = new HashSet<>();
Set removed = new HashSet<>();
try (AutoLock l = lock.lock()) {
if (replace) {
removed.addAll(removeRemotePresences(oortURL));
}
for (String userId : userIds) {
SetiLocation location = new SetiLocation(userId, oortURL);
if (present) {
if (associateRemote(userId, location)) {
added.add(userId);
}
} else {
if (disassociate(userId, location)) {
removed.add(userId);
}
}
}
}
Set toRemove = new HashSet<>(removed);
toRemove.removeAll(added);
for (String userId : toRemove) {
notifyPresenceRemoved(oortURL, userId);
}
added.removeAll(removed);
for (String userId : added) {
notifyPresenceAdded(oortURL, userId);
}
if (presence.get(SetiPresence.ALIVE_FIELD) == Boolean.TRUE) {
// Message sent on startup by the remote Seti, push our associations
OortComet oortComet = _oort.findComet(oortURL);
if (oortComet != null) {
Set associatedUserIds = getAssociatedUserIds();
if (_logger.isDebugEnabled()) {
_logger.debug("Pushing associated users {} to comet {}", associatedUserIds, oortURL);
}
ClientSessionChannel channel = oortComet.getChannel(generateSetiChannel(generateSetiId(oortURL)));
channel.publish(new SetiPresence(associatedUserIds));
}
}
}
public void addPresenceListener(PresenceListener listener) {
_presenceListeners.add(listener);
}
public void removePresenceListener(PresenceListener listener) {
_presenceListeners.remove(listener);
}
public void removePresenceListeners() {
_presenceListeners.clear();
}
private void notifyPresenceAdded(String oortURL, String userId) {
PresenceListener.Event event = new PresenceListener.Event(this, userId, oortURL);
for (PresenceListener listener : _presenceListeners) {
try {
listener.presenceAdded(event);
} catch (Throwable x) {
_logger.info("Exception while invoking listener " + listener, x);
}
}
}
private void notifyPresenceRemoved(String oortURL, String userId) {
PresenceListener.Event event = new PresenceListener.Event(this, userId, oortURL);
for (PresenceListener listener : _presenceListeners) {
try {
listener.presenceRemoved(event);
} catch (Throwable x) {
_logger.info("Exception while invoking listener " + listener, x);
}
}
}
/**
* Receives a seti message.
*
* @param message the seti message received
*/
protected void receiveMessage(Map message) {
String userId = (String)message.get(SetiMessage.USER_ID_FIELD);
String channel = (String)message.get(SetiMessage.CHANNEL_FIELD);
Object data = message.get(SetiMessage.DATA_FIELD);
Set copy = new HashSet<>();
try (AutoLock l = lock.lock()) {
Set locations = _uid2Location.get(userId);
if (locations != null) {
// Consider cometA, cometB and cometC and a user that is associated
// in both cometA and cometB. When cometC sends a message to the user,
// it knows that the user is in both cometA and cometB (thanks to presence
// messages) and will send a message to both cometA and cometB.
// But cometA also knows from presence messages that the user is also in
// cometB and should not forward the message arriving from cometC to cometB
// since cometC will take care of sending to cometB.
// Hence, we forward the message only locally
for (Location location : locations) {
if (location instanceof LocalLocation) {
copy.add(location);
}
}
}
}
if (_logger.isDebugEnabled()) {
_logger.debug("Received message {} for locations {}", message, copy);
}
for (Location location : copy) {
location.receive(userId, channel, data);
}
}
@SuppressWarnings("unchecked")
private Set convertPresenceUsers(Map presence) {
Object value = presence.get(SetiPresence.USER_IDS_FIELD);
if (value instanceof Set) {
return (Set)value;
}
if (value instanceof Collection) {
return new HashSet<>((Collection)value);
}
if (value.getClass().isArray()) {
Set result = new HashSet<>();
for (Object item : (Object[])value) {
result.add(item.toString());
}
return result;
}
throw new IllegalArgumentException();
}
@Override
public void dump(Appendable out, String indent) throws IOException {
boolean detailed = ((BayeuxServerImpl)getOort().getBayeuxServer()).isDetailedDump();
if (detailed) {
List>> locations;
try (AutoLock l = lock.lock()) {
locations = new TreeMap<>(_uid2Location).entrySet().stream()
.map(entry -> new AbstractMap.SimpleEntry<>(entry.getKey(), new HashSet<>(entry.getValue())))
.collect(Collectors.toList());
}
Dumpable.dumpObjects(out, indent, this, new DumpableCollection("locations", locations));
} else {
int size;
try (AutoLock l = lock.lock()) {
size = _uid2Location.size();
}
Dumpable.dumpObjects(out, indent, this, "locations size=" + size);
}
}
@Override
public String toString() {
return String.format("%s[%s]", getClass().getName(), getId());
}
/**
* The representation of where a user is.
*/
protected interface Location {
public void send(String toUser, String toChannel, Object data);
public void receive(String toUser, String toChannel, Object data);
@Override
public int hashCode();
@Override
public boolean equals(Object obj);
}
/**
* A Location that represent a user connected to a local comet.
*/
protected class LocalLocation implements Location, ServerSession.RemovedListener {
private final String _userId;
private final ServerSession _session;
protected LocalLocation(String userId, ServerSession session) {
_userId = userId;
_session = session;
}
@Override
public void send(String toUser, String toChannel, Object data) {
_session.deliver(Seti.this._session, toChannel, data, Promise.noop());
}
@Override
public void receive(String toUser, String toChannel, Object data) {
send(toUser, toChannel, data);
}
@Override
public void removed(ServerSession session, ServerMessage message, boolean timeout) {
disassociate(_userId, session);
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (!(obj instanceof LocalLocation)) {
return false;
}
LocalLocation that = (LocalLocation)obj;
return _userId.equals(that._userId) && _session.getId().equals(that._session.getId());
}
@Override
public int hashCode() {
return Objects.hash(_userId, _session.getId());
}
@Override
public String toString() {
return String.format("%s[%s]", getClass().getSimpleName(), _session);
}
}
/**
* A Location that represent a user connected to a remote comet.
*/
protected class SetiLocation implements Location {
private final String _userId;
private final String _oortURL;
private final String _setiChannel;
protected SetiLocation(String userId, String oortURL) {
_userId = userId;
_oortURL = oortURL;
_setiChannel = oortURL == null ? SETI_ALL_CHANNEL : generateSetiChannel(generateSetiId(oortURL));
}
@Override
public void send(String toUser, String toChannel, Object data) {
_session.getChannel(_setiChannel).publish(new SetiMessage(toUser, toChannel, data));
}
@Override
public void receive(String toUser, String toChannel, Object data) {
// A message has been sent to this comet because the sender thought
// the user was in this comet. If it were, we would have found a
// LocalLocation, but instead found this SetiLocation.
// Therefore, the user must have moved to this seti location, and
// we forward the message.
send(toUser, toChannel, data);
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (!(obj instanceof SetiLocation)) {
return false;
}
SetiLocation that = (SetiLocation)obj;
return _userId.equals(that._userId) && _setiChannel.equals(that._setiChannel);
}
@Override
public int hashCode() {
return Objects.hash(_userId, _setiChannel);
}
@Override
public String toString() {
return String.format("%s[%s]", getClass().getSimpleName(), _setiChannel);
}
}
private class SetiMessage extends HashMap {
private static final String USER_ID_FIELD = "userId";
private static final String CHANNEL_FIELD = "channel";
private static final String SETI_ID_FIELD = "setiId";
private static final String DATA_FIELD = "data";
private SetiMessage(String toUser, String toChannel, Object data) {
super(4);
put(USER_ID_FIELD, toUser);
put(CHANNEL_FIELD, toChannel);
put(SETI_ID_FIELD, _setiId);
put(DATA_FIELD, data);
}
}
private class SetiPresence extends HashMap {
private static final String USER_IDS_FIELD = "userIds";
private static final String OORT_URL_FIELD = "oortURL";
private static final String ALIVE_FIELD = "alive";
private static final String PRESENCE_FIELD = "presence";
private static final String REPLACE_FIELD = "replace";
private SetiPresence(boolean present, String userId) {
this(present, Set.of(userId), false);
}
private SetiPresence(Set userIds) {
this(true, userIds, true);
}
private SetiPresence(boolean present, Set userIds, boolean replace) {
super(4);
put(USER_IDS_FIELD, userIds);
put(OORT_URL_FIELD, _oort.getURL());
put(PRESENCE_FIELD, present);
put(REPLACE_FIELD, replace);
}
}
/**
* Listener interface that gets notified of remote Seti presence events.
*/
public interface PresenceListener extends EventListener {
/**
* Callback method invoked when a presence is added to a remote Seti
*
* @param event the presence event
*/
public default void presenceAdded(Event event) {
}
/**
* Callback method invoked when a presence is removed from a remote Seti
*
* @param event the presence event
*/
public default void presenceRemoved(Event event) {
}
/**
* Seti presence event object, delivered to {@link PresenceListener} methods.
*/
public static class Event extends EventObject {
private final String userId;
private final String url;
public Event(Seti source, String userId, String url) {
super(source);
this.userId = userId;
this.url = url;
}
/**
* @return the local Seti object
*/
public Seti getSeti() {
return (Seti)getSource();
}
/**
* @return the userId associated to this presence event
*/
public String getUserId() {
return userId;
}
/**
* @return the Oort URL where this presence event happened
*/
public String getOortURL() {
return url;
}
/**
* @return whether this presence event happened on the local Seti or on a remote Seti
*/
public boolean isLocal() {
return getSeti().getOort().getURL().equals(getOortURL());
}
@Override
public String toString() {
return String.format("%s[%s %s on %s]",
getClass().getName(),
getUserId(),
isLocal() ? "local" : "remote",
getSeti());
}
}
}
private class CometListener implements Oort.CometListener {
@Override
public void cometJoined(Event event) {
String oortURL = event.getCometURL();
OortComet oortComet = _oort.findComet(oortURL);
if (_logger.isDebugEnabled()) {
_logger.debug("Comet joined: {} with {}", oortURL, oortComet);
}
if (oortComet != null) {
ClientSessionChannel channel = oortComet.getChannel(generateSetiChannel(generateSetiId(oortURL)));
Set userIds = getAssociatedUserIds();
if (_logger.isDebugEnabled()) {
_logger.debug("Pushing associated users {} to comet {}", userIds, oortURL);
}
channel.publish(new SetiPresence(userIds));
}
}
@Override
public void cometLeft(Event event) {
String oortURL = event.getCometURL();
if (_logger.isDebugEnabled()) {
_logger.debug("Comet left: {}", oortURL);
}
removePresences(oortURL);
}
}
private class InitialStateListener implements ServerChannel.SubscriptionListener {
@Override
public void subscribed(ServerSession session, ServerChannel channel, ServerMessage message) {
if (!session.isLocalSession()) {
Set associatedUserIds = getAssociatedUserIds();
if (_logger.isDebugEnabled()) {
_logger.debug("Broadcasting associated users {}", associatedUserIds);
}
SetiPresence presence = new SetiPresence(associatedUserIds);
presence.put(SetiPresence.ALIVE_FIELD, true);
session.deliver(_session, SETI_ALL_CHANNEL, presence, Promise.noop());
}
}
}
}
© 2015 - 2025 Weber Informatics LLC | Privacy Policy