Back-port fix for OPENDJ-1112: LoadBalancing connection factories need bett...

Matthew Swift

30.25.2013 ad636a8035cc19f5a412b6b97b3f95ba37d0fe9a

 opendj-ldap-sdk/src/main/java/org/forgerock/opendj/ldap/AbstractLoadBalancingAlgorithm.java

@@ -162,12 +162,17 @@
        }

        private void notifyOffline(final ErrorResultException error) {
            // Save the error in case the load-balancer is exhausted.
            lastFailure = error;

            if (isOperational.getAndSet(false)) {
                // Transition from online to offline.
                if (DEBUG_LOG.isLoggable(Level.WARNING)) {
                    DEBUG_LOG.warning(String.format(
                            "Connection factory '%s' is no longer operational: %s", factory, error
                                    .getMessage()));
                synchronized (listenerLock) {
                    try {
                        listener.handleConnectionFactoryOffline(factory, error);
                    } catch (RuntimeException e) {
                        handleListenerException(e);
                    }
                }

                synchronized (stateLock) {
@@ -189,9 +194,12 @@
        private void notifyOnline() {
            if (!isOperational.getAndSet(true)) {
                // Transition from offline to online.
                if (DEBUG_LOG.isLoggable(Level.INFO)) {
                    DEBUG_LOG.info(String.format("Connection factory'%s' is now operational",
                            factory));
                synchronized (listenerLock) {
                    try {
                        listener.handleConnectionFactoryOnline(factory);
                    } catch (RuntimeException e) {
                        handleListenerException(e);
                    }
                }

                synchronized (stateLock) {
@@ -207,6 +215,13 @@
                }
            }
        }

        private void handleListenerException(RuntimeException e) {
            if (DEBUG_LOG.isLoggable(Level.SEVERE)) {
                DEBUG_LOG.log(Level.SEVERE,
                        "A run-time error occurred while processing a load-balancer event", e);
            }
        }
    }

    private final class MonitorRunnable implements Runnable {
@@ -222,9 +237,54 @@
        }
    }

    /**
     * A default event listener which just logs the event.
     */
    private static final LoadBalancerEventListener DEFAULT_LISTENER =
            new LoadBalancerEventListener() {

                @Override
                public void handleConnectionFactoryOnline(ConnectionFactory factory) {
                    // Transition from offline to online.
                    if (DEBUG_LOG.isLoggable(Level.INFO)) {
                        DEBUG_LOG.info(String.format("Connection factory'%s' is now operational",
                                factory));
                    }
                }

                @Override
                public void handleConnectionFactoryOffline(ConnectionFactory factory,
                        ErrorResultException error) {
                    if (DEBUG_LOG.isLoggable(Level.WARNING)) {
                        DEBUG_LOG.warning(String.format(
                                "Connection factory '%s' is no longer operational: %s", factory,
                                error.getMessage()));
                    }
                }
            };

    private final List<MonitoredConnectionFactory> monitoredFactories;
    private final ReferenceCountedObject<ScheduledExecutorService>.Reference scheduler;
    private final Object stateLock = new Object();

    /**
     * The last connection failure which caused a connection factory to be
     * marked offline. This is used in order to help diagnose problems when the
     * load-balancer has exhausted all of its factories.
     */
    private volatile ErrorResultException lastFailure = null;

    /**
     * The event listener which should be notified when connection factories go
     * on or off-line.
     */
    private final LoadBalancerEventListener listener;

    /**
     * Ensures that events are notified one at a time.
     */
    private final Object listenerLock = new Object();

    /**
     * Guarded by stateLock.
     */
@@ -237,17 +297,9 @@
    private ScheduledFuture<?> monitoringFuture;
    private AtomicBoolean isClosed = new AtomicBoolean();

    AbstractLoadBalancingAlgorithm(final Collection<ConnectionFactory> factories) {
        this(factories, 1, TimeUnit.SECONDS, null);
    }

    AbstractLoadBalancingAlgorithm(final Collection<ConnectionFactory> factories,
            final long interval, final TimeUnit unit) {
        this(factories, interval, unit, null);
    }

    AbstractLoadBalancingAlgorithm(final Collection<ConnectionFactory> factories,
            final long interval, final TimeUnit unit, final ScheduledExecutorService scheduler) {
            final LoadBalancerEventListener listener, final long interval, final TimeUnit unit,
            final ScheduledExecutorService scheduler) {
        Validator.ensureNotNull(factories, unit);

        this.monitoredFactories = new ArrayList<MonitoredConnectionFactory>(factories.size());
@@ -258,6 +310,7 @@
        this.scheduler = DEFAULT_SCHEDULER.acquireIfNull(scheduler);
        this.monitoringInterval = interval;
        this.monitoringIntervalTimeUnit = unit;
        this.listener = listener != null ? listener : DEFAULT_LISTENER;
    }

    @Override
@@ -335,6 +388,6 @@
         * timeout period.
         */
        throw newErrorResult(ResultCode.CLIENT_SIDE_CONNECT_ERROR,
                "No operational connection factories available");
                "No operational connection factories available", lastFailure);
    }
}