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.databroker.actors.dds;
10 import akka.actor.ActorRef;
11 import akka.actor.Status;
12 import java.util.concurrent.CompletableFuture;
13 import java.util.concurrent.CompletionStage;
14 import org.opendaylight.controller.cluster.access.concepts.LocalHistoryIdentifier;
15 import org.opendaylight.controller.cluster.datastore.actors.client.ClientActorBehavior;
16 import org.opendaylight.controller.cluster.datastore.actors.client.ClientActorContext;
17 import org.slf4j.Logger;
18 import org.slf4j.LoggerFactory;
21 * {@link ClientActorBehavior} acting as an intermediary between the backend actors and the DistributedDataStore
24 * This class is not visible outside of this package because it breaks the actor containment. Services provided to
25 * Java world outside of actor containment are captured in {@link DistributedDataStoreClient}.
27 * IMPORTANT: this class breaks actor containment via methods implementing {@link DistributedDataStoreClient} contract.
28 * When touching internal state, be mindful of the execution context from which execution context, Actor
29 * or POJO, is the state being accessed or modified.
31 * THREAD SAFETY: this class must always be kept thread-safe, so that both the Actor System thread and the application
32 * threads can run concurrently. All state transitions must be made in a thread-safe manner. When in
33 * doubt, feel free to synchronize on this object.
35 * PERFORMANCE: this class lies in a performance-critical fast path. All code needs to be concise and efficient, but
36 * performance must not come at the price of correctness. Any optimizations need to be carefully analyzed
37 * for correctness and performance impact.
39 * TRADE-OFFS: part of the functionality runs in application threads without switching contexts, which makes it ideal
40 * for performing work and charging applications for it. That has two positive effects:
41 * - CPU usage is distributed across applications, minimizing work done in the actor thread
42 * - CPU usage provides back-pressure towards the application.
44 * @author Robert Varga
46 final class DistributedDataStoreClientBehavior extends ClientActorBehavior implements DistributedDataStoreClient {
47 private static final Logger LOG = LoggerFactory.getLogger(DistributedDataStoreClientBehavior.class);
48 private static final Object SHUTDOWN = new Object() {
50 public String toString() {
55 private long nextHistoryId;
57 DistributedDataStoreClientBehavior(final ClientActorContext context) {
63 // Methods below are invoked from the client actor thread
68 protected void haltClient(final Throwable cause) {
69 // FIXME: Add state flushing here once we have state
72 private void createLocalHistory(final CreateLocalHistoryCommand command) {
73 final CompletableFuture<ClientLocalHistory> future = command.future();
74 final LocalHistoryIdentifier historyId = new LocalHistoryIdentifier(getIdentifier(), nextHistoryId++);
75 LOG.debug("{}: creating a new local history {} for {}", persistenceId(), historyId, future);
77 // FIXME: initiate backend instantiation
78 future.completeExceptionally(new UnsupportedOperationException("Not implemented yet"));
82 protected ClientActorBehavior onCommand(final Object command) {
83 if (command instanceof CreateLocalHistoryCommand) {
84 createLocalHistory((CreateLocalHistoryCommand) command);
85 } else if (command instanceof GetClientRequest) {
86 ((GetClientRequest) command).getReplyTo().tell(new Status.Success(this), ActorRef.noSender());
87 } else if (SHUTDOWN.equals(command)) {
88 // FIXME: Add shutdown procedures here
91 LOG.warn("{}: ignoring unhandled command {}", persistenceId(), command);
99 // Methods below are invoked from application threads
104 public CompletionStage<ClientLocalHistory> createLocalHistory() {
105 final CreateLocalHistoryCommand command = new CreateLocalHistoryCommand();
106 self().tell(command, ActorRef.noSender());
107 return command.future();
111 public void close() {
112 self().tell(SHUTDOWN, ActorRef.noSender());