2 * Copyright (c) 2014 Cisco Systems, Inc. and others. All rights reserved.
4 * This program and the accompanying materials are made available under the
5 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
6 * and is available at http://www.eclipse.org/legal/epl-v10.html
8 package org.opendaylight.mdsal.dom.broker;
10 import static com.google.common.base.Preconditions.checkArgument;
12 import com.google.common.annotations.VisibleForTesting;
13 import com.google.common.collect.ImmutableList;
14 import com.google.common.collect.ImmutableMultimap;
15 import com.google.common.collect.ImmutableMultimap.Builder;
16 import com.google.common.collect.Multimap;
17 import com.google.common.collect.Multimaps;
18 import com.google.common.util.concurrent.ListenableFuture;
19 import com.google.common.util.concurrent.ThreadFactoryBuilder;
20 import com.lmax.disruptor.EventHandler;
21 import com.lmax.disruptor.InsufficientCapacityException;
22 import com.lmax.disruptor.PhasedBackoffWaitStrategy;
23 import com.lmax.disruptor.WaitStrategy;
24 import com.lmax.disruptor.dsl.Disruptor;
25 import com.lmax.disruptor.dsl.ProducerType;
26 import java.util.Arrays;
27 import java.util.Collection;
28 import java.util.List;
30 import java.util.concurrent.ExecutorService;
31 import java.util.concurrent.Executors;
32 import java.util.concurrent.ScheduledFuture;
33 import java.util.concurrent.ScheduledThreadPoolExecutor;
34 import java.util.concurrent.TimeUnit;
35 import org.opendaylight.mdsal.dom.api.DOMNotification;
36 import org.opendaylight.mdsal.dom.api.DOMNotificationListener;
37 import org.opendaylight.mdsal.dom.api.DOMNotificationPublishService;
38 import org.opendaylight.mdsal.dom.api.DOMNotificationService;
39 import org.opendaylight.mdsal.dom.spi.DOMNotificationSubscriptionListener;
40 import org.opendaylight.mdsal.dom.spi.DOMNotificationSubscriptionListenerRegistry;
41 import org.opendaylight.yangtools.concepts.AbstractListenerRegistration;
42 import org.opendaylight.yangtools.concepts.ListenerRegistration;
43 import org.opendaylight.yangtools.util.ListenerRegistry;
44 import org.opendaylight.yangtools.util.concurrent.FluentFutures;
45 import org.opendaylight.yangtools.yang.model.api.SchemaPath;
46 import org.slf4j.Logger;
47 import org.slf4j.LoggerFactory;
50 * Joint implementation of {@link DOMNotificationPublishService} and {@link DOMNotificationService}. Provides
51 * routing of notifications from publishers to subscribers.
54 * Internal implementation works by allocating a two-handler Disruptor. The first handler delivers notifications
55 * to subscribed listeners and the second one notifies whoever may be listening on the returned future. Registration
56 * state tracking is performed by a simple immutable multimap -- when a registration or unregistration occurs we
57 * re-generate the entire map from scratch and set it atomically. While registrations/unregistrations synchronize
58 * on this instance, notifications do not take any locks here.
61 * The fully-blocking {@link #publish(long, DOMNotification, Collection)}
62 * and non-blocking {@link #offerNotification(DOMNotification)}
63 * are realized using the Disruptor's native operations. The bounded-blocking {@link
64 * #offerNotification(DOMNotification, long, TimeUnit)}
65 * is realized by arming a background wakeup interrupt.
67 public class DOMNotificationRouter implements AutoCloseable, DOMNotificationPublishService,
68 DOMNotificationService, DOMNotificationSubscriptionListenerRegistry {
70 private static final Logger LOG = LoggerFactory.getLogger(DOMNotificationRouter.class);
71 private static final ListenableFuture<Void> NO_LISTENERS = FluentFutures.immediateNullFluentFuture();
72 private static final WaitStrategy DEFAULT_STRATEGY = PhasedBackoffWaitStrategy.withLock(
73 1L, 30L, TimeUnit.MILLISECONDS);
74 private static final EventHandler<DOMNotificationRouterEvent> DISPATCH_NOTIFICATIONS =
75 (event, sequence, endOfBatch) -> event.deliverNotification();
76 private static final EventHandler<DOMNotificationRouterEvent> NOTIFY_FUTURE =
77 (event, sequence, endOfBatch) -> event.setFuture();
79 private final ListenerRegistry<DOMNotificationSubscriptionListener> subscriptionListeners =
80 ListenerRegistry.create();
81 private final Disruptor<DOMNotificationRouterEvent> disruptor;
82 private final ScheduledThreadPoolExecutor observer;
83 private final ExecutorService executor;
85 private volatile Multimap<SchemaPath, AbstractListenerRegistration<? extends DOMNotificationListener>> listeners =
86 ImmutableMultimap.of();
89 DOMNotificationRouter(final int queueDepth, final WaitStrategy strategy) {
90 observer = new ScheduledThreadPoolExecutor(1,
91 new ThreadFactoryBuilder().setDaemon(true).setNameFormat("DOMNotificationRouter-observer-%d").build());
92 executor = Executors.newCachedThreadPool(
93 new ThreadFactoryBuilder().setDaemon(true).setNameFormat("DOMNotificationRouter-listeners-%d").build());
94 disruptor = new Disruptor<>(DOMNotificationRouterEvent.FACTORY, queueDepth,
95 new ThreadFactoryBuilder().setNameFormat("DOMNotificationRouter-disruptor-%d").build(),
96 ProducerType.MULTI, strategy);
97 disruptor.handleEventsWith(DISPATCH_NOTIFICATIONS);
98 disruptor.after(DISPATCH_NOTIFICATIONS).handleEventsWith(NOTIFY_FUTURE);
102 public static DOMNotificationRouter create(final int queueDepth) {
103 return new DOMNotificationRouter(queueDepth, DEFAULT_STRATEGY);
106 public static DOMNotificationRouter create(final int queueDepth, final long spinTime, final long parkTime,
107 final TimeUnit unit) {
108 checkArgument(Long.lowestOneBit(queueDepth) == Long.highestOneBit(queueDepth),
109 "Queue depth %s is not power-of-two", queueDepth);
110 return new DOMNotificationRouter(queueDepth, PhasedBackoffWaitStrategy.withLock(spinTime, parkTime, unit));
114 public synchronized <T extends DOMNotificationListener> ListenerRegistration<T> registerNotificationListener(
115 final T listener, final Collection<SchemaPath> types) {
116 final AbstractListenerRegistration<T> reg = new AbstractListenerRegistration<>(listener) {
118 protected void removeRegistration() {
119 synchronized (DOMNotificationRouter.this) {
120 replaceListeners(ImmutableMultimap.copyOf(Multimaps.filterValues(listeners,
121 input -> input != this)));
126 if (!types.isEmpty()) {
127 final Builder<SchemaPath, AbstractListenerRegistration<? extends DOMNotificationListener>> b =
128 ImmutableMultimap.builder();
131 for (final SchemaPath t : types) {
135 replaceListeners(b.build());
142 public <T extends DOMNotificationListener> ListenerRegistration<T> registerNotificationListener(
143 final T listener, final SchemaPath... types) {
144 return registerNotificationListener(listener, Arrays.asList(types));
148 * Swaps registered listeners and triggers notification update.
150 * @param newListeners is used to notify listenerTypes changed
152 private void replaceListeners(
153 final Multimap<SchemaPath, AbstractListenerRegistration<? extends DOMNotificationListener>> newListeners) {
154 listeners = newListeners;
155 notifyListenerTypesChanged(newListeners.keySet());
158 @SuppressWarnings("checkstyle:IllegalCatch")
159 private void notifyListenerTypesChanged(final Set<SchemaPath> typesAfter) {
160 final List<? extends DOMNotificationSubscriptionListener> listenersAfter =
161 subscriptionListeners.streamListeners().collect(ImmutableList.toImmutableList());
162 executor.execute(() -> {
163 for (final DOMNotificationSubscriptionListener subListener : listenersAfter) {
165 subListener.onSubscriptionChanged(typesAfter);
166 } catch (final Exception e) {
167 LOG.warn("Uncaught exception during invoking listener {}", subListener, e);
174 public <L extends DOMNotificationSubscriptionListener> ListenerRegistration<L> registerSubscriptionListener(
176 final Set<SchemaPath> initialTypes = listeners.keySet();
177 executor.execute(() -> listener.onSubscriptionChanged(initialTypes));
178 return subscriptionListeners.register(listener);
181 private ListenableFuture<Void> publish(final long seq, final DOMNotification notification,
182 final Collection<AbstractListenerRegistration<? extends DOMNotificationListener>> subscribers) {
183 final DOMNotificationRouterEvent event = disruptor.get(seq);
184 final ListenableFuture<Void> future = event.initialize(notification, subscribers);
185 disruptor.getRingBuffer().publish(seq);
190 public ListenableFuture<? extends Object> putNotification(final DOMNotification notification)
191 throws InterruptedException {
192 final Collection<AbstractListenerRegistration<? extends DOMNotificationListener>> subscribers =
193 listeners.get(notification.getType());
194 if (subscribers.isEmpty()) {
198 final long seq = disruptor.getRingBuffer().next();
199 return publish(seq, notification, subscribers);
202 @SuppressWarnings("checkstyle:IllegalCatch")
204 ListenableFuture<? extends Object> tryPublish(final DOMNotification notification,
205 final Collection<AbstractListenerRegistration<? extends DOMNotificationListener>> subscribers) {
208 seq = disruptor.getRingBuffer().tryNext();
209 } catch (final InsufficientCapacityException e) {
210 return DOMNotificationPublishService.REJECTED;
213 return publish(seq, notification, subscribers);
217 public ListenableFuture<? extends Object> offerNotification(final DOMNotification notification) {
218 final Collection<AbstractListenerRegistration<? extends DOMNotificationListener>> subscribers =
219 listeners.get(notification.getType());
220 if (subscribers.isEmpty()) {
224 return tryPublish(notification, subscribers);
228 public ListenableFuture<? extends Object> offerNotification(final DOMNotification notification, final long timeout,
229 final TimeUnit unit) throws InterruptedException {
230 final Collection<AbstractListenerRegistration<? extends DOMNotificationListener>> subscribers =
231 listeners.get(notification.getType());
232 if (subscribers.isEmpty()) {
235 // Attempt to perform a non-blocking publish first
236 final ListenableFuture<?> noBlock = tryPublish(notification, subscribers);
237 if (!DOMNotificationPublishService.REJECTED.equals(noBlock)) {
242 final Thread publishThread = Thread.currentThread();
243 ScheduledFuture<?> timerTask = observer.schedule(publishThread::interrupt, timeout, unit);
244 final ListenableFuture<?> withBlock = putNotification(notification);
245 timerTask.cancel(true);
246 if (observer.getQueue().size() > 50) {
250 } catch (InterruptedException e) {
251 return DOMNotificationPublishService.REJECTED;
256 public void close() {
257 disruptor.shutdown();
263 ExecutorService executor() {
268 ExecutorService observer() {
273 Multimap<SchemaPath, ?> listeners() {
278 ListenerRegistry<DOMNotificationSubscriptionListener> subscriptionListeners() {
279 return subscriptionListeners;