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