/*
* Copyright (c) 2014 Cisco Systems, Inc. and others. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 which accompanies this distribution,
* and is available at http://www.eclipse.org/legal/epl-v10.html
*/
package org.opendaylight.mdsal.dom.api;
import com.google.common.util.concurrent.ListenableFuture;
import java.util.concurrent.TimeUnit;
import org.checkerframework.checker.index.qual.NonNegative;
import org.eclipse.jdt.annotation.NonNull;
import org.opendaylight.yangtools.util.concurrent.FluentFutures;
/**
* A {@link DOMService} which allows its user to publish top-level (YANG 1.0) {@link DOMNotification}s. It provides two
* styles of initiating the notification delivery, similar to {@link java.util.concurrent.BlockingQueue}:
*
* a put-style method which waits until the implementation can accept the notification for delivery, and
* an offer-style method, which attempts to enqueue the notification, but allows the caller to specify that it
* should never wait, or put an upper bound on how long it is going to wait
*
*/
public interface DOMNotificationPublishService extends DOMService {
/**
* Well-known value indicating that the implementation is currently not
* able to accept a notification.
*/
ListenableFuture REJECTED = FluentFutures.immediateFailedFluentFuture(
new DOMNotificationRejectedException("Unacceptable blocking conditions encountered"));
/**
* Publish a notification. The result of this method is a {@link ListenableFuture} which will
* complete once the notification has been delivered to all immediate registrants. The type of
* the object resulting from the future is not defined and implementations may use it to convey
* additional information related to the publishing process.
* Abstract subclasses can refine the return type as returning a promise of a more specific
* type, e.g.:
* public interface DeliveryStatus { int getListenerCount(); } ListenableFuture<? extends
* DeliveryStatus>[ putNotification(DOMNotification notification);
* Once the Future succeeds, the resulting object can be queried for traits using instanceof,
* e.g:
* // Can block when (for example) the implemention's ThreadPool queue is full Object o =
* service.putNotification(notif).get(); if (o instanceof DeliveryStatus) { DeliveryStatus ds =
* (DeliveryStatus)o; LOG.debug("Notification was received by {} listeners",
* ds.getListenerCount();); } }
* In case an implementation is running out of resources, it can block the calling thread until
* enough resources become available to accept the notification for processing, or it is
* interrupted.
*
*
* Caution: completion here means that the implementation has completed processing of the
* notification. This does not mean that all existing registrants have seen the notification.
* Most importantly, the delivery process at other cluster nodes may have not begun yet.
*
* @param notification Notification to be published.
* @return A listenable future which will report completion when the service has finished
* propagating the notification to its immediate registrants.
* @throws InterruptedException if interrupted while waiting
* @throws NullPointerException if notification is null.
*/
@NonNull ListenableFuture extends Object> putNotification(@NonNull DOMNotification notification)
throws InterruptedException;
/**
* Attempt to publish a notification. The result of this method is a {@link ListenableFuture}
* which will complete once the notification has been delivered to all immediate registrants.
* The type of the object resulting from the future is not defined and implementations may use
* it to convey additional information related to the publishing process. Unlike
* {@link #putNotification(DOMNotification)}, this method is guaranteed not to block if the
* underlying implementation encounters contention.
*
* @param notification Notification to be published.
* @return A listenable future which will report completion when the service has finished
* propagating the notification to its immediate registrants, or {@link #REJECTED} if
* resource constraints prevent the implementation from accepting the notification for
* delivery.
* @throws NullPointerException if notification is null.
*/
@NonNull ListenableFuture extends Object> offerNotification(@NonNull DOMNotification notification);
/**
* Attempt to publish a notification. The result of this method is a {@link ListenableFuture}
* which will complete once the notification has been delivered to all immediate registrants.
* The type of the object resulting from the future is not defined and implementations may use
* it to convey additional information related to the publishing process. Unlike
* {@link #putNotification(DOMNotification)}, this method is guaranteed to block more than the
* specified timeout.
*
* @param notification Notification to be published.
* @param timeout how long to wait before giving up, in units of unit
* @param unit a TimeUnit determining how to interpret the timeout parameter
* @return A listenable future which will report completion when the service has finished
* propagating the notification to its immediate registrants, or {@link #REJECTED} if
* resource constraints prevent the implementation from accepting the notification for
* delivery.
* @throws InterruptedException if interrupted while waiting
* @throws NullPointerException if notification or unit is null.
* @throws IllegalArgumentException if timeout is negative.
*/
@NonNull ListenableFuture extends Object> offerNotification(@NonNull DOMNotification notification,
@NonNegative long timeout, @NonNull TimeUnit unit) throws InterruptedException;
}