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.api;
10 import com.google.common.util.concurrent.Futures;
11 import com.google.common.util.concurrent.ListenableFuture;
12 import java.util.concurrent.TimeUnit;
13 import javax.annotation.Nonnegative;
14 import javax.annotation.Nonnull;
15 import org.opendaylight.controller.sal.core.api.BrokerService;
18 * A {@link DOMService} which allows its user to send {@link DOMNotification}s. It
19 * provides two styles of initiating the notification delivery, similar to
20 * {@link java.util.concurrent.BlockingQueue}:
21 * - a put-style method which waits until the implementation can accept the notification
23 * - an offer-style method, which attempts to enqueue the notification, but allows
24 * the caller to specify that it should never wait, or put an upper bound on how
25 * long it is going to wait.
27 public interface DOMNotificationPublishService extends DOMService, BrokerService {
29 * Well-known value indicating that the implementation is currently not
30 * able to accept a notification.
32 ListenableFuture<Object> REJECTED = Futures.immediateFailedFuture(new Throwable("Unacceptable blocking conditions encountered"));
35 * Publish a notification. The result of this method is a {@link ListenableFuture}
36 * which will complete once the notification has been delivered to all immediate
37 * registrants. The type of the object resulting from the future is not defined
38 * and implementations may use it to convey additional information related to the
41 * Abstract subclasses can refine the return type as returning a promise of a
42 * more specific type, e.g.:
44 * public interface DeliveryStatus { int getListenerCount(); }
45 * ListenableFuture<? extends DeliveryStatus> putNotification(DOMNotification notification);
47 * Once the Future succeeds, the resulting object can be queried for traits using
50 * // Can block when (for example) the implemention's ThreadPool queue is full
51 * Object o = service.putNotification(notif).get();
52 * if (o instanceof DeliveryStatus) {
53 * DeliveryStatus ds = (DeliveryStatus)o;
54 * LOG.debug("Notification was received by {} listeners", ds.getListenerCount(););
58 * In case an implementation is running out of resources, it can block the calling
59 * thread until enough resources become available to accept the notification for
60 * processing, or it is interrupted.
62 * Caution: completion here means that the implementation has completed processing
63 * of the notification. This does not mean that all existing registrants
64 * have seen the notification. Most importantly, the delivery process at
65 * other cluster nodes may have not begun yet.
67 * @param notification Notification to be published.
68 * @return A listenable future which will report completion when the service
69 * has finished propagating the notification to its immediate registrants.
70 * @throws InterruptedException if interrupted while waiting
71 * @throws NullPointerException if notification is null.
73 @Nonnull ListenableFuture<? extends Object> putNotification(@Nonnull DOMNotification notification) throws InterruptedException;
76 * Attempt to publish a notification. The result of this method is a {@link ListenableFuture}
77 * which will complete once the notification has been delivered to all immediate
78 * registrants. The type of the object resulting from the future is not defined
79 * and implementations may use it to convey additional information related to the
80 * publishing process. Unlike {@link #putNotification(DOMNotification)}, this method
81 * is guaranteed not to block if the underlying implementation encounters contention.
83 * @param notification Notification to be published.
84 * @return A listenable future which will report completion when the service
85 * has finished propagating the notification to its immediate registrants,
86 * or {@value #REJECTED} if resource constraints prevent
87 * the implementation from accepting the notification for delivery.
88 * @throws NullPointerException if notification is null.
90 @Nonnull ListenableFuture<? extends Object> offerNotification(@Nonnull DOMNotification notification);
93 * Attempt to publish a notification. The result of this method is a {@link ListenableFuture}
94 * which will complete once the notification has been delivered to all immediate
95 * registrants. The type of the object resulting from the future is not defined
96 * and implementations may use it to convey additional information related to the
97 * publishing process. Unlike {@link #putNotification(DOMNotification)}, this method
98 * is guaranteed to block more than the specified timeout.
100 * @param notification Notification to be published.
101 * @param timeout how long to wait before giving up, in units of unit
102 * @param unit a TimeUnit determining how to interpret the timeout parameter
103 * @return A listenable future which will report completion when the service
104 * has finished propagating the notification to its immediate registrants,
105 * or {@value #REJECTED} if resource constraints prevent
106 * the implementation from accepting the notification for delivery.
107 * @throws InterruptedException if interrupted while waiting
108 * @throws NullPointerException if notification or unit is null.
109 * @throws IllegalArgumentException if timeout is negative.
111 @Nonnull ListenableFuture<? extends Object> offerNotification(@Nonnull DOMNotification notification,
112 @Nonnegative long timeout, @Nonnull TimeUnit unit) throws InterruptedException;