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 com.google.common.base.Preconditions;
11 import com.google.common.base.Predicate;
12 import com.google.common.collect.ImmutableList;
13 import com.google.common.collect.ImmutableMultimap;
14 import com.google.common.collect.ImmutableMultimap.Builder;
15 import com.google.common.collect.Multimap;
16 import com.google.common.collect.Multimaps;
17 import com.google.common.util.concurrent.Futures;
18 import com.google.common.util.concurrent.ListenableFuture;
19 import com.lmax.disruptor.EventHandler;
20 import com.lmax.disruptor.InsufficientCapacityException;
21 import com.lmax.disruptor.PhasedBackoffWaitStrategy;
22 import com.lmax.disruptor.WaitStrategy;
23 import com.lmax.disruptor.dsl.Disruptor;
24 import com.lmax.disruptor.dsl.ProducerType;
25 import java.util.Arrays;
26 import java.util.Collection;
27 import java.util.List;
29 import java.util.concurrent.ExecutorService;
30 import java.util.concurrent.Executors;
31 import java.util.concurrent.TimeUnit;
32 import org.opendaylight.mdsal.dom.api.DOMNotification;
33 import org.opendaylight.mdsal.dom.api.DOMNotificationListener;
34 import org.opendaylight.mdsal.dom.api.DOMNotificationPublishService;
35 import org.opendaylight.mdsal.dom.api.DOMNotificationService;
36 import org.opendaylight.mdsal.dom.spi.DOMNotificationSubscriptionListener;
37 import org.opendaylight.mdsal.dom.spi.DOMNotificationSubscriptionListenerRegistry;
38 import org.opendaylight.yangtools.concepts.AbstractListenerRegistration;
39 import org.opendaylight.yangtools.concepts.ListenerRegistration;
40 import org.opendaylight.yangtools.util.ListenerRegistry;
41 import org.opendaylight.yangtools.yang.model.api.SchemaPath;
42 import org.slf4j.Logger;
43 import org.slf4j.LoggerFactory;
46 * Joint implementation of {@link DOMNotificationPublishService} and {@link DOMNotificationService}. Provides
47 * routing of notifications from publishers to subscribers.
50 * Internal implementation works by allocating a two-handler Disruptor. The first handler delivers notifications
51 * to subscribed listeners and the second one notifies whoever may be listening on the returned future. Registration
52 * state tracking is performed by a simple immutable multimap -- when a registration or unregistration occurs we
53 * re-generate the entire map from scratch and set it atomically. While registrations/unregistrations synchronize
54 * on this instance, notifications do not take any locks here.
57 * The fully-blocking {@link #publish(long, DOMNotification, Collection)}
58 * and non-blocking {@link #offerNotification(DOMNotification)}
59 * are realized using the Disruptor's native operations. The bounded-blocking {@link
60 * #offerNotification(DOMNotification, long, TimeUnit)}
61 * is realized by arming a background wakeup interrupt.
63 public final class DOMNotificationRouter implements AutoCloseable, DOMNotificationPublishService,
64 DOMNotificationService, DOMNotificationSubscriptionListenerRegistry {
66 private static final Logger LOG = LoggerFactory.getLogger(DOMNotificationRouter.class);
67 private static final ListenableFuture<Void> NO_LISTENERS = Futures.immediateFuture(null);
68 private static final WaitStrategy DEFAULT_STRATEGY = PhasedBackoffWaitStrategy.withLock(
69 1L, 30L, TimeUnit.MILLISECONDS);
70 private static final EventHandler<DOMNotificationRouterEvent> DISPATCH_NOTIFICATIONS =
71 new EventHandler<DOMNotificationRouterEvent>() {
73 public void onEvent(final DOMNotificationRouterEvent event, final long sequence,
74 final boolean endOfBatch) throws Exception {
75 event.deliverNotification();
79 private static final EventHandler<DOMNotificationRouterEvent> NOTIFY_FUTURE =
80 new EventHandler<DOMNotificationRouterEvent>() {
82 public void onEvent(final DOMNotificationRouterEvent event, final long sequence, final boolean endOfBatch) {
87 private final Disruptor<DOMNotificationRouterEvent> disruptor;
88 private final ExecutorService executor;
89 private volatile Multimap<SchemaPath, ListenerRegistration<? extends
90 DOMNotificationListener>> listeners = ImmutableMultimap.of();
91 private final ListenerRegistry<DOMNotificationSubscriptionListener> subscriptionListeners =
92 ListenerRegistry.create();
94 @SuppressWarnings("unchecked")
95 private DOMNotificationRouter(final ExecutorService executor, final int queueDepth, final WaitStrategy strategy) {
96 this.executor = Preconditions.checkNotNull(executor);
98 disruptor = new Disruptor<>(DOMNotificationRouterEvent.FACTORY,
99 queueDepth, executor, ProducerType.MULTI, strategy);
100 disruptor.handleEventsWith(DISPATCH_NOTIFICATIONS);
101 disruptor.after(DISPATCH_NOTIFICATIONS).handleEventsWith(NOTIFY_FUTURE);
105 public static DOMNotificationRouter create(final int queueDepth) {
106 final ExecutorService executor = Executors.newCachedThreadPool();
108 return new DOMNotificationRouter(executor, queueDepth, DEFAULT_STRATEGY);
111 public static DOMNotificationRouter create(final int queueDepth, final long spinTime,
112 final long parkTime, final TimeUnit unit) {
113 final ExecutorService executor = Executors.newCachedThreadPool();
114 final WaitStrategy strategy = PhasedBackoffWaitStrategy.withLock(spinTime, parkTime, unit);
116 return new DOMNotificationRouter(executor, queueDepth, strategy);
120 public synchronized <T extends DOMNotificationListener> ListenerRegistration<T> registerNotificationListener(
121 final T listener, final Collection<SchemaPath> types) {
122 final ListenerRegistration<T> reg = new AbstractListenerRegistration<T>(listener) {
124 protected void removeRegistration() {
125 final ListenerRegistration<T> me = this;
127 synchronized (DOMNotificationRouter.this) {
128 replaceListeners(ImmutableMultimap.copyOf(Multimaps.filterValues(listeners,
129 new Predicate<ListenerRegistration<? extends DOMNotificationListener>>() {
131 public boolean apply(final ListenerRegistration<? extends DOMNotificationListener> input) {
139 if (!types.isEmpty()) {
140 final Builder<SchemaPath, ListenerRegistration<? extends DOMNotificationListener>> b =
141 ImmutableMultimap.builder();
144 for (final SchemaPath t : types) {
148 replaceListeners(b.build());
155 public <T extends DOMNotificationListener> ListenerRegistration<T> registerNotificationListener(
156 final T listener, final SchemaPath... types) {
157 return registerNotificationListener(listener, Arrays.asList(types));
161 * Swaps registered listeners and triggers notification update.
163 * @param newListeners is used to notify listenerTypes changed
165 private void replaceListeners(
166 final Multimap<SchemaPath, ListenerRegistration<? extends DOMNotificationListener>> newListeners) {
167 listeners = newListeners;
168 notifyListenerTypesChanged(newListeners.keySet());
171 @SuppressWarnings("checkstyle:IllegalCatch")
172 private void notifyListenerTypesChanged(final Set<SchemaPath> typesAfter) {
173 final List<ListenerRegistration<DOMNotificationSubscriptionListener>> listenersAfter =
174 ImmutableList.copyOf(subscriptionListeners.getListeners());
175 executor.submit(new Runnable() {
179 for (final ListenerRegistration<DOMNotificationSubscriptionListener> subListener : listenersAfter) {
181 subListener.getInstance().onSubscriptionChanged(typesAfter);
182 } catch (final Exception e) {
183 LOG.warn("Uncaught exception during invoking listener {}", subListener.getInstance(), e);
191 public <L extends DOMNotificationSubscriptionListener> ListenerRegistration<L> registerSubscriptionListener(
193 final Set<SchemaPath> initialTypes = listeners.keySet();
194 executor.submit(new Runnable() {
198 listener.onSubscriptionChanged(initialTypes);
201 return subscriptionListeners.registerWithType(listener);
204 private ListenableFuture<Void> publish(final long seq, final DOMNotification notification,
205 final Collection<ListenerRegistration<? extends DOMNotificationListener>> subscribers) {
206 final DOMNotificationRouterEvent event = disruptor.get(seq);
207 final ListenableFuture<Void> future = event.initialize(notification, subscribers);
208 disruptor.getRingBuffer().publish(seq);
213 public ListenableFuture<? extends Object> putNotification(final DOMNotification notification)
214 throws InterruptedException {
215 final Collection<ListenerRegistration<? extends DOMNotificationListener>> subscribers =
216 listeners.get(notification.getType());
217 if (subscribers.isEmpty()) {
221 final long seq = disruptor.getRingBuffer().next();
222 return publish(seq, notification, subscribers);
225 @SuppressWarnings("checkstyle:IllegalCatch")
226 private ListenableFuture<? extends Object> tryPublish(final DOMNotification notification,
227 final Collection<ListenerRegistration<? extends DOMNotificationListener>> subscribers) {
230 seq = disruptor.getRingBuffer().tryNext();
231 } catch (final InsufficientCapacityException e) {
232 return DOMNotificationPublishService.REJECTED;
235 return publish(seq, notification, subscribers);
239 public ListenableFuture<? extends Object> offerNotification(final DOMNotification notification) {
240 final Collection<ListenerRegistration<? extends DOMNotificationListener>> subscribers =
241 listeners.get(notification.getType());
242 if (subscribers.isEmpty()) {
246 return tryPublish(notification, subscribers);
250 public ListenableFuture<? extends Object> offerNotification(final DOMNotification notification, final long timeout,
251 final TimeUnit unit) throws InterruptedException {
252 final Collection<ListenerRegistration<? extends DOMNotificationListener>> subscribers =
253 listeners.get(notification.getType());
254 if (subscribers.isEmpty()) {
258 // Attempt to perform a non-blocking publish first
259 final ListenableFuture<? extends Object> noBlock = tryPublish(notification, subscribers);
260 if (!DOMNotificationPublishService.REJECTED.equals(noBlock)) {
265 * FIXME: we need a background thread, which will watch out for blocking too long. Here
266 * we will arm a tasklet for it and synchronize delivery of interrupt properly.
268 throw new UnsupportedOperationException("Not implemented yet");
272 public void close() {
273 disruptor.shutdown();