--- /dev/null
+/*
+ * 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.controller.md.sal.dom.api;
+
+import com.google.common.util.concurrent.Futures;
+import com.google.common.util.concurrent.ListenableFuture;
+import java.util.concurrent.TimeUnit;
+import javax.annotation.Nonnegative;
+import javax.annotation.Nonnull;
+
+/**
+ * A {@link DOMService} which allows its user to send {@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<Object> REJECTED = Futures.immediateFailedFuture(new Throwable("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 {@value #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 {@value #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;
+}
Code Review / controller.git / blobdiff