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.controller.md.sal.dom.broker.impl;
10 import com.google.common.base.Preconditions;
11 import com.google.common.collect.ImmutableList;
12 import com.google.common.collect.ImmutableMultimap;
13 import com.google.common.collect.ImmutableMultimap.Builder;
14 import com.google.common.collect.Multimap;
15 import com.google.common.collect.Multimaps;
16 import com.google.common.util.concurrent.Futures;
17 import com.google.common.util.concurrent.ListenableFuture;
18 import com.lmax.disruptor.EventHandler;
19 import com.lmax.disruptor.InsufficientCapacityException;
20 import com.lmax.disruptor.PhasedBackoffWaitStrategy;
21 import com.lmax.disruptor.WaitStrategy;
22 import com.lmax.disruptor.dsl.Disruptor;
23 import com.lmax.disruptor.dsl.ProducerType;
24 import java.util.Arrays;
25 import java.util.Collection;
26 import java.util.List;
28 import java.util.concurrent.ExecutorService;
29 import java.util.concurrent.Executors;
30 import java.util.concurrent.TimeUnit;
31 import org.opendaylight.controller.md.sal.dom.api.DOMNotification;
32 import org.opendaylight.controller.md.sal.dom.api.DOMNotificationListener;
33 import org.opendaylight.controller.md.sal.dom.api.DOMNotificationPublishService;
34 import org.opendaylight.controller.md.sal.dom.api.DOMNotificationService;
35 import org.opendaylight.controller.md.sal.dom.spi.DOMNotificationSubscriptionListener;
36 import org.opendaylight.controller.md.sal.dom.spi.DOMNotificationSubscriptionListenerRegistry;
37 import org.opendaylight.yangtools.concepts.AbstractListenerRegistration;
38 import org.opendaylight.yangtools.concepts.ListenerRegistration;
39 import org.opendaylight.yangtools.util.ListenerRegistry;
40 import org.opendaylight.yangtools.yang.model.api.SchemaPath;
41 import org.slf4j.Logger;
42 import org.slf4j.LoggerFactory;
45 * Joint implementation of {@link DOMNotificationPublishService} and {@link DOMNotificationService}. Provides
46 * routing of notifications from publishers to subscribers.
49 * Internal implementation works by allocating a two-handler Disruptor. The first handler delivers notifications
50 * to subscribed listeners and the second one notifies whoever may be listening on the returned future. Registration
51 * state tracking is performed by a simple immutable multimap -- when a registration or unregistration occurs we
52 * re-generate the entire map from scratch and set it atomically. While registrations/unregistrations synchronize
53 * on this instance, notifications do not take any locks here.
56 * The fully-blocking {@link #publish(long, DOMNotification, Collection)} and non-blocking
57 * {@link #offerNotification(DOMNotification)}
58 * are realized using the Disruptor's native operations. The bounded-blocking
59 * {@link #offerNotification(DOMNotification, long, TimeUnit)}
60 * is realized by arming a background wakeup interrupt.
62 public final class DOMNotificationRouter implements AutoCloseable, DOMNotificationPublishService,
63 DOMNotificationService, DOMNotificationSubscriptionListenerRegistry {
65 private static final Logger LOG = LoggerFactory.getLogger(DOMNotificationRouter.class);
66 private static final ListenableFuture<Void> NO_LISTENERS = Futures.immediateFuture(null);
67 private static final WaitStrategy DEFAULT_STRATEGY = PhasedBackoffWaitStrategy
68 .withLock(1L, 30L, TimeUnit.MILLISECONDS);
69 private static final EventHandler<DOMNotificationRouterEvent> DISPATCH_NOTIFICATIONS
70 = (event, sequence, endOfBatch) -> event.deliverNotification();
71 private static final EventHandler<DOMNotificationRouterEvent> NOTIFY_FUTURE = (event, sequence, endOfBatch) -> event
74 private final Disruptor<DOMNotificationRouterEvent> disruptor;
75 private final ExecutorService executor;
76 private volatile Multimap<SchemaPath, ListenerRegistration<? extends DOMNotificationListener>> listeners
77 = ImmutableMultimap.of();
78 private final ListenerRegistry<DOMNotificationSubscriptionListener> subscriptionListeners = ListenerRegistry
81 @SuppressWarnings("unchecked")
82 private DOMNotificationRouter(final ExecutorService executor, final int queueDepth, final WaitStrategy strategy) {
83 this.executor = Preconditions.checkNotNull(executor);
85 disruptor = new Disruptor<>(DOMNotificationRouterEvent.FACTORY, queueDepth, executor, ProducerType.MULTI,
87 disruptor.handleEventsWith(DISPATCH_NOTIFICATIONS);
88 disruptor.after(DISPATCH_NOTIFICATIONS).handleEventsWith(NOTIFY_FUTURE);
92 public static DOMNotificationRouter create(final int queueDepth) {
93 final ExecutorService executor = Executors.newCachedThreadPool();
95 return new DOMNotificationRouter(executor, queueDepth, DEFAULT_STRATEGY);
98 public static DOMNotificationRouter create(final int queueDepth, final long spinTime, final long parkTime,
99 final TimeUnit unit) {
100 Preconditions.checkArgument(Long.lowestOneBit(queueDepth) == Long.highestOneBit(queueDepth),
101 "Queue depth %s is not power-of-two", queueDepth);
102 final ExecutorService executor = Executors.newCachedThreadPool();
103 final WaitStrategy strategy = PhasedBackoffWaitStrategy.withLock(spinTime, parkTime, unit);
105 return new DOMNotificationRouter(executor, queueDepth, strategy);
109 public synchronized <T extends DOMNotificationListener> ListenerRegistration<T> registerNotificationListener(
110 final T listener, final Collection<SchemaPath> types) {
111 final ListenerRegistration<T> reg = new AbstractListenerRegistration<T>(listener) {
113 protected void removeRegistration() {
114 final ListenerRegistration<T> me = this;
116 synchronized (DOMNotificationRouter.this) {
117 replaceListeners(ImmutableMultimap.copyOf(Multimaps.filterValues(listeners, input -> input != me)));
122 if (!types.isEmpty()) {
123 final Builder<SchemaPath, ListenerRegistration<? extends DOMNotificationListener>> b = ImmutableMultimap
127 for (final SchemaPath t : types) {
131 replaceListeners(b.build());
138 public <T extends DOMNotificationListener> ListenerRegistration<T> registerNotificationListener(final T listener,
142 return registerNotificationListener(listener, Arrays.asList(types));
146 * Swaps registered listeners and triggers notification update.
148 * @param newListeners listeners
150 private void replaceListeners(
151 final Multimap<SchemaPath, ListenerRegistration<? extends DOMNotificationListener>> newListeners) {
152 listeners = newListeners;
153 notifyListenerTypesChanged(newListeners.keySet());
156 @SuppressWarnings("checkstyle:IllegalCatch")
157 private void notifyListenerTypesChanged(final Set<SchemaPath> typesAfter) {
158 final List<ListenerRegistration<DOMNotificationSubscriptionListener>> listenersAfter = ImmutableList
159 .copyOf(subscriptionListeners.getListeners());
160 executor.execute(() -> {
161 for (final ListenerRegistration<DOMNotificationSubscriptionListener> subListener : listenersAfter) {
163 subListener.getInstance().onSubscriptionChanged(typesAfter);
164 } catch (final Exception e) {
165 LOG.warn("Uncaught exception during invoking listener {}", subListener.getInstance(), e);
172 public <L extends DOMNotificationSubscriptionListener> ListenerRegistration<L> registerSubscriptionListener(
174 final Set<SchemaPath> initialTypes = listeners.keySet();
175 executor.execute(() -> listener.onSubscriptionChanged(initialTypes));
176 return subscriptionListeners.registerWithType(listener);
179 private ListenableFuture<Void> publish(final long seq, final DOMNotification notification,
180 final Collection<ListenerRegistration<? extends DOMNotificationListener>>
182 final DOMNotificationRouterEvent event = disruptor.get(seq);
183 final ListenableFuture<Void> future = event.initialize(notification, subscribers);
184 disruptor.getRingBuffer().publish(seq);
189 public ListenableFuture<?> putNotification(final DOMNotification notification) throws InterruptedException {
190 final Collection<ListenerRegistration<? extends DOMNotificationListener>> subscribers = listeners
191 .get(notification.getType());
192 if (subscribers.isEmpty()) {
196 final long seq = disruptor.getRingBuffer().next();
197 return publish(seq, notification, subscribers);
200 private ListenableFuture<?> tryPublish(final DOMNotification notification,
201 final Collection<ListenerRegistration<? extends DOMNotificationListener>>
205 seq = disruptor.getRingBuffer().tryNext();
206 } catch (final InsufficientCapacityException e) {
207 return DOMNotificationPublishService.REJECTED;
210 return publish(seq, notification, subscribers);
214 public ListenableFuture<?> offerNotification(final DOMNotification notification) {
215 final Collection<ListenerRegistration<? extends DOMNotificationListener>> subscribers = listeners
216 .get(notification.getType());
217 if (subscribers.isEmpty()) {
221 return tryPublish(notification, subscribers);
225 public ListenableFuture<?> offerNotification(final DOMNotification notification, final long timeout,
226 final TimeUnit unit) throws InterruptedException {
227 final Collection<ListenerRegistration<? extends DOMNotificationListener>> subscribers = listeners
228 .get(notification.getType());
229 if (subscribers.isEmpty()) {
233 // Attempt to perform a non-blocking publish first
234 final ListenableFuture<?> noBlock = tryPublish(notification, subscribers);
235 if (!DOMNotificationPublishService.REJECTED.equals(noBlock)) {
240 * FIXME: we need a background thread, which will watch out for blocking too long. Here
241 * we will arm a tasklet for it and synchronize delivery of interrupt properly.
243 throw new UnsupportedOperationException("Not implemented yet");
247 public void close() {
248 disruptor.shutdown();