2 * Copyright (c) 2016 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.cluster.access.client;
10 import akka.actor.ActorRef;
11 import java.util.concurrent.CompletionStage;
12 import javax.annotation.Nonnull;
15 * Caching resolver which resolves a cookie to a leader {@link ActorRef}. This class needs to be specialized by the
16 * client. It is used by {@link ClientActorBehavior} for request dispatch. Results are cached until they are invalidated
17 * by either the client actor (when a message timeout is detected) and by the specific frontend (on explicit
18 * invalidation or when updated information becomes available).
21 * If the completion stage returned by this interface's methods fails with a
22 * {@link org.opendaylight.controller.cluster.access.concepts.RequestException}, it will be forwarded to all
23 * outstanding requests towards the leader. If it fails with a {@link java.util.concurrent.TimeoutException},
24 * resolution process will be retried. If it fails with any other cause, it will we wrapped as a
25 * {@link org.opendaylight.controller.cluster.access.concepts.RuntimeRequestException} wrapping that cause.
27 * @author Robert Varga
29 public abstract class BackendInfoResolver<T extends BackendInfo> {
31 * Request resolution of a particular backend identified by a cookie. This request can be satisfied from the cache.
33 * @param cookie Backend cookie
34 * @return A {@link CompletionStage} resulting in information about the backend
37 public abstract CompletionStage<? extends T> getBackendInfo(@Nonnull Long cookie);
40 * Request re-resolution of a particular backend identified by a cookie, indicating a particular information as
41 * being stale. If the implementation's cache holds the stale information, it should be purged.
43 * @param cookie Backend cookie
44 * @param staleInfo Stale backend information
45 * @return A {@link CompletionStage} resulting in information about the backend
48 public abstract CompletionStage<? extends T> refreshBackendInfo(@Nonnull Long cookie, @Nonnull T staleInfo);