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/**
*
* Copyright 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.jivesoftware.smack;
import java.io.IOException;
import java.lang.ref.WeakReference;
import java.util.Map;
import java.util.Random;
import java.util.Set;
import java.util.WeakHashMap;
import java.util.concurrent.CopyOnWriteArraySet;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.jivesoftware.smack.XMPPException.StreamErrorException;
import org.jivesoftware.smack.packet.StreamError;
import org.jivesoftware.smack.util.Async;
/**
* Handles the automatic reconnection process. Every time a connection is dropped without
* the application explicitly closing it, the manager automatically tries to reconnect to
* the server.
*
* There are two possible reconnection policies:
*
* {@link ReconnectionPolicy#RANDOM_INCREASING_DELAY} - The reconnection mechanism will try to reconnect periodically:
*
* - For the first minute it will attempt to connect once every ten seconds.
*
- For the next five minutes it will attempt to connect once a minute.
*
- If that fails it will indefinitely try to connect once every five minutes.
*
*
* {@link ReconnectionPolicy#FIXED_DELAY} - The reconnection mechanism will try to reconnect after a fixed delay
* independently from the number of reconnection attempts already performed.
*
* Interrupting the reconnection thread will abort the reconnection mechanism.
*
*
* @author Francisco Vives
* @author Luca Stucchi
*/
public final class ReconnectionManager {
private static final Logger LOGGER = Logger.getLogger(ReconnectionManager.class.getName());
private static final Map INSTANCES = new WeakHashMap();
/**
* Get a instance of ReconnectionManager for the given connection.
*
* @param connection TODO javadoc me please
* @return a ReconnectionManager for the connection.
*/
public static synchronized ReconnectionManager getInstanceFor(AbstractXMPPConnection connection) {
ReconnectionManager reconnectionManager = INSTANCES.get(connection);
if (reconnectionManager == null) {
reconnectionManager = new ReconnectionManager(connection);
INSTANCES.put(connection, reconnectionManager);
}
return reconnectionManager;
}
static {
XMPPConnectionRegistry.addConnectionCreationListener(new ConnectionCreationListener() {
@Override
public void connectionCreated(XMPPConnection connection) {
if (connection instanceof AbstractXMPPConnection) {
ReconnectionManager.getInstanceFor((AbstractXMPPConnection) connection);
}
}
});
}
private static boolean enabledPerDefault = false;
/**
* Set if the automatic reconnection mechanism will be enabled per default for new XMPP connections. The default is
* 'false'.
*
* @param enabled TODO javadoc me please
*/
public static void setEnabledPerDefault(boolean enabled) {
enabledPerDefault = enabled;
}
/**
* Get the current default reconnection mechanism setting for new XMPP connections.
*
* @return true if new connection will come with an enabled reconnection mechanism
*/
public static boolean getEnabledPerDefault() {
return enabledPerDefault;
}
private final Set reconnectionListeners = new CopyOnWriteArraySet<>();
// Holds the connection to the server
private final WeakReference weakRefConnection;
private final int randomBase = new Random().nextInt(13) + 2; // between 2 and 15 seconds
private final Runnable reconnectionRunnable;
private static int defaultFixedDelay = 15;
private static ReconnectionPolicy defaultReconnectionPolicy = ReconnectionPolicy.RANDOM_INCREASING_DELAY;
private volatile int fixedDelay = defaultFixedDelay;
private volatile ReconnectionPolicy reconnectionPolicy = defaultReconnectionPolicy;
/**
* Set the default fixed delay in seconds between the reconnection attempts. Also set the
* default connection policy to {@link ReconnectionPolicy#FIXED_DELAY}
*
* @param fixedDelay Delay expressed in seconds
*/
public static void setDefaultFixedDelay(int fixedDelay) {
defaultFixedDelay = fixedDelay;
setDefaultReconnectionPolicy(ReconnectionPolicy.FIXED_DELAY);
}
/**
* Set the default Reconnection Policy to use.
*
* @param reconnectionPolicy TODO javadoc me please
*/
public static void setDefaultReconnectionPolicy(ReconnectionPolicy reconnectionPolicy) {
defaultReconnectionPolicy = reconnectionPolicy;
}
/**
* Add a new reconnection listener.
*
* @param listener the listener to add
* @return true if the listener was not already added
* @since 4.2.2
*/
public boolean addReconnectionListener(ReconnectionListener listener) {
return reconnectionListeners.add(listener);
}
/**
* Remove a reconnection listener.
* @param listener the listener to remove
* @return true if the listener was active and got removed.
* @since 4.2.2
*/
public boolean removeReconnectionListener(ReconnectionListener listener) {
return reconnectionListeners.remove(listener);
}
/**
* Set the fixed delay in seconds between the reconnection attempts Also set the connection
* policy to {@link ReconnectionPolicy#FIXED_DELAY}.
*
* @param fixedDelay Delay expressed in seconds
*/
public void setFixedDelay(int fixedDelay) {
this.fixedDelay = fixedDelay;
setReconnectionPolicy(ReconnectionPolicy.FIXED_DELAY);
}
/**
* Set the Reconnection Policy to use.
*
* @param reconnectionPolicy TODO javadoc me please
*/
public void setReconnectionPolicy(ReconnectionPolicy reconnectionPolicy) {
this.reconnectionPolicy = reconnectionPolicy;
}
/**
* Flag that indicates if a reconnection should be attempted when abruptly disconnected.
*/
private boolean automaticReconnectEnabled = false;
boolean done = false;
private Thread reconnectionThread;
private ReconnectionManager(AbstractXMPPConnection connection) {
weakRefConnection = new WeakReference<>(connection);
reconnectionRunnable = new Runnable() {
/**
* Holds the current number of reconnection attempts
*/
private int attempts = 0;
/**
* Returns the number of seconds until the next reconnection attempt.
*
* @return the number of seconds until the next reconnection attempt.
*/
private int timeDelay() {
attempts++;
// Delay variable to be assigned
int delay;
switch (reconnectionPolicy) {
case FIXED_DELAY:
delay = fixedDelay;
break;
case RANDOM_INCREASING_DELAY:
if (attempts > 13) {
delay = randomBase * 6 * 5; // between 2.5 and 7.5 minutes (~5 minutes)
}
else if (attempts > 7) {
delay = randomBase * 6; // between 30 and 90 seconds (~1 minutes)
}
else {
delay = randomBase; // 10 seconds
}
break;
default:
throw new AssertionError("Unknown reconnection policy " + reconnectionPolicy);
}
return delay;
}
/**
* The process will try the reconnection until the connection succeed or the user cancel it
*/
@Override
public void run() {
final AbstractXMPPConnection connection = weakRefConnection.get();
if (connection == null) {
return;
}
// Reset attempts to zero since a new reconnection cycle is started once this runs.
attempts = 0;
// The process will try to reconnect until the connection is established or
// the user cancel the reconnection process AbstractXMPPConnection.disconnect().
while (isReconnectionPossible(connection)) {
// Find how much time we should wait until the next reconnection
int remainingSeconds = timeDelay();
// Sleep until we're ready for the next reconnection attempt. Notify
// listeners once per second about how much time remains before the next
// reconnection attempt.
while (remainingSeconds > 0) {
if (!isReconnectionPossible(connection)) {
return;
}
try {
Thread.sleep(1000);
remainingSeconds--;
for (ReconnectionListener listener : reconnectionListeners) {
listener.reconnectingIn(remainingSeconds);
}
}
catch (InterruptedException e) {
LOGGER.log(Level.FINE, "Reconnection Thread was interrupted, aborting reconnection mechanism", e);
// Exit the reconnection thread in case it was interrupted.
return;
}
}
for (ReconnectionListener listener : reconnectionListeners) {
listener.reconnectingIn(0);
}
if (!isReconnectionPossible(connection)) {
return;
}
// Makes a reconnection attempt
try {
try {
connection.connect();
}
catch (SmackException.AlreadyConnectedException e) {
LOGGER.log(Level.FINER, "Connection was already connected on reconnection attempt", e);
}
connection.login();
}
catch (SmackException.AlreadyLoggedInException e) {
// This can happen if another thread concurrently triggers a reconnection
// and/or login. Obviously it should not be handled as a reconnection
// failure. See also SMACK-725.
LOGGER.log(Level.FINER, "Reconnection not required, was already logged in", e);
}
catch (SmackException | IOException | XMPPException e) {
// Fires the failed reconnection notification
for (ReconnectionListener listener : reconnectionListeners) {
listener.reconnectionFailed(e);
}
// Failed to reconnect, try again.
continue;
} catch (InterruptedException e) {
LOGGER.log(Level.FINE, "Reconnection Thread was interrupted, aborting reconnection mechanism", e);
// Exit the reconnection thread in case it was interrupted.
return;
}
// Successfully reconnected .
return;
}
}
};
// If the reconnection mechanism is enable per default, enable it for this ReconnectionManager instance
if (getEnabledPerDefault()) {
enableAutomaticReconnection();
}
}
/**
* Enable the automatic reconnection mechanism. Does nothing if already enabled.
*/
public synchronized void enableAutomaticReconnection() {
if (automaticReconnectEnabled) {
return;
}
XMPPConnection connection = weakRefConnection.get();
if (connection == null) {
throw new IllegalStateException("Connection instance no longer available");
}
connection.addConnectionListener(connectionListener);
automaticReconnectEnabled = true;
}
/**
* Disable the automatic reconnection mechanism. Does nothing if already disabled.
*/
public synchronized void disableAutomaticReconnection() {
if (!automaticReconnectEnabled) {
return;
}
XMPPConnection connection = weakRefConnection.get();
if (connection == null) {
throw new IllegalStateException("Connection instance no longer available");
}
connection.removeConnectionListener(connectionListener);
automaticReconnectEnabled = false;
}
/**
* Returns if the automatic reconnection mechanism is enabled. You can disable the reconnection mechanism with
* {@link #disableAutomaticReconnection} and enable the mechanism with {@link #enableAutomaticReconnection()}.
*
* @return true, if the reconnection mechanism is enabled.
*/
public synchronized boolean isAutomaticReconnectEnabled() {
return automaticReconnectEnabled;
}
/**
* Returns true if the reconnection mechanism is enabled.
*
* @return true if automatic reconnection is allowed.
*/
private boolean isReconnectionPossible(XMPPConnection connection) {
return !done && !connection.isConnected()
&& isAutomaticReconnectEnabled();
}
/**
* Starts a reconnection mechanism if it was configured to do that.
* The algorithm is been executed when the first connection error is detected.
*/
private synchronized void reconnect() {
XMPPConnection connection = this.weakRefConnection.get();
if (connection == null) {
LOGGER.fine("Connection is null, will not reconnect");
return;
}
// Since there is no thread running, creates a new one to attempt
// the reconnection.
// avoid to run duplicated reconnectionThread -- fd: 16/09/2010
if (reconnectionThread != null && reconnectionThread.isAlive())
return;
reconnectionThread = Async.go(reconnectionRunnable,
"Smack Reconnection Manager (" + connection.getConnectionCounter() + ')');
}
/**
* Abort a possibly running reconnection mechanism.
*
* @since 4.2.2
*/
public synchronized void abortPossiblyRunningReconnection() {
if (reconnectionThread == null) {
return;
}
reconnectionThread.interrupt();
reconnectionThread = null;
}
private final ConnectionListener connectionListener = new ConnectionListener() {
@Override
public void connectionClosed() {
done = true;
}
@Override
public void authenticated(XMPPConnection connection, boolean resumed) {
done = false;
}
@Override
public void connectionClosedOnError(Exception e) {
done = false;
if (!isAutomaticReconnectEnabled()) {
return;
}
if (e instanceof StreamErrorException) {
StreamErrorException xmppEx = (StreamErrorException) e;
StreamError error = xmppEx.getStreamError();
if (StreamError.Condition.conflict == error.getCondition()) {
return;
}
}
reconnect();
}
};
/**
* Reconnection Policy, where {@link ReconnectionPolicy#RANDOM_INCREASING_DELAY} is the default policy used by smack and {@link ReconnectionPolicy#FIXED_DELAY} implies
* a fixed amount of time between reconnection attempts.
*/
public enum ReconnectionPolicy {
/**
* Default policy classically used by smack, having an increasing delay related to the
* overall number of attempts.
*/
RANDOM_INCREASING_DELAY,
/**
* Policy using fixed amount of time between reconnection attempts.
*/
FIXED_DELAY,
}
}