| /* |
| * Copyright 2016 Open Networking Laboratory |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.onosproject.store.primitives.resources.impl; |
| |
| import io.atomix.catalyst.util.Listener; |
| import io.atomix.copycat.client.CopycatClient; |
| import io.atomix.resource.Resource; |
| import io.atomix.resource.ResourceTypeInfo; |
| |
| import java.util.List; |
| import java.util.Map; |
| import java.util.Set; |
| import java.util.concurrent.CompletableFuture; |
| import java.util.function.Consumer; |
| |
| import org.onosproject.cluster.Leadership; |
| import org.onosproject.cluster.NodeId; |
| import org.onosproject.event.Change; |
| import org.onosproject.store.service.AsyncLeaderElector; |
| |
| import com.google.common.collect.Sets; |
| |
| /** |
| * Distributed resource providing the {@link AsyncLeaderElector} primitive. |
| */ |
| @ResourceTypeInfo(id = -152, |
| stateMachine = AtomixLeaderElectorState.class, |
| typeResolver = AtomixLeaderElectorCommands.TypeResolver.class) |
| public class AtomixLeaderElector extends Resource<AtomixLeaderElector> |
| implements AsyncLeaderElector { |
| private final Set<Consumer<Change<Leadership>>> leadershipChangeListeners = |
| Sets.newConcurrentHashSet(); |
| |
| public static final String CHANGE_SUBJECT = "leadershipChangeEvents"; |
| private Listener<Change<Leadership>> listener; |
| |
| public AtomixLeaderElector(CopycatClient client, Resource.Options options) { |
| super(client, options); |
| } |
| |
| @Override |
| public String name() { |
| return null; |
| } |
| |
| @Override |
| public CompletableFuture<AtomixLeaderElector> open() { |
| return super.open().thenApply(result -> { |
| client.onEvent(CHANGE_SUBJECT, this::handleEvent); |
| return result; |
| }); |
| } |
| |
| private void handleEvent(List<Change<Leadership>> changes) { |
| changes.forEach(change -> leadershipChangeListeners.forEach(l -> l.accept(change))); |
| } |
| |
| @Override |
| public CompletableFuture<Leadership> run(String topic, NodeId nodeId) { |
| return submit(new AtomixLeaderElectorCommands.Run(topic, nodeId)); |
| } |
| |
| @Override |
| public CompletableFuture<Void> withdraw(String topic) { |
| return submit(new AtomixLeaderElectorCommands.Withdraw(topic)); |
| } |
| |
| @Override |
| public CompletableFuture<Boolean> anoint(String topic, NodeId nodeId) { |
| return submit(new AtomixLeaderElectorCommands.Anoint(topic, nodeId)); |
| } |
| |
| @Override |
| public CompletableFuture<Boolean> promote(String topic, NodeId nodeId) { |
| return submit(new AtomixLeaderElectorCommands.Promote(topic, nodeId)); |
| } |
| |
| @Override |
| public CompletableFuture<Void> evict(NodeId nodeId) { |
| return submit(new AtomixLeaderElectorCommands.Evict(nodeId)); |
| } |
| |
| @Override |
| public CompletableFuture<Leadership> getLeadership(String topic) { |
| return submit(new AtomixLeaderElectorCommands.GetLeadership(topic)); |
| } |
| |
| @Override |
| public CompletableFuture<Map<String, Leadership>> getLeaderships() { |
| return submit(new AtomixLeaderElectorCommands.GetAllLeaderships()); |
| } |
| |
| public CompletableFuture<Set<String>> getElectedTopics(NodeId nodeId) { |
| return submit(new AtomixLeaderElectorCommands.GetElectedTopics(nodeId)); |
| } |
| |
| /** |
| * Leadership change listener context. |
| */ |
| private final class LeadershipChangeListener implements Listener<Change<Leadership>> { |
| private final Consumer<Change<Leadership>> listener; |
| |
| private LeadershipChangeListener(Consumer<Change<Leadership>> listener) { |
| this.listener = listener; |
| } |
| |
| @Override |
| public void accept(Change<Leadership> change) { |
| listener.accept(change); |
| } |
| |
| @Override |
| public void close() { |
| synchronized (AtomixLeaderElector.this) { |
| submit(new AtomixLeaderElectorCommands.Unlisten()); |
| } |
| } |
| } |
| |
| @Override |
| public CompletableFuture<Void> addChangeListener(Consumer<Change<Leadership>> consumer) { |
| leadershipChangeListeners.add(consumer); |
| return setupListener(); |
| } |
| |
| @Override |
| public CompletableFuture<Void> removeChangeListener(Consumer<Change<Leadership>> consumer) { |
| leadershipChangeListeners.remove(consumer); |
| return teardownListener(); |
| } |
| |
| private CompletableFuture<Void> setupListener() { |
| if (listener == null && !leadershipChangeListeners.isEmpty()) { |
| Consumer<Change<Leadership>> changeConsumer = change -> { |
| leadershipChangeListeners.forEach(consumer -> consumer.accept(change)); |
| }; |
| return submit(new AtomixLeaderElectorCommands.Listen()) |
| .thenAccept(v -> listener = new LeadershipChangeListener(changeConsumer)); |
| } |
| return CompletableFuture.completedFuture(null); |
| } |
| |
| private CompletableFuture<Void> teardownListener() { |
| if (listener != null && leadershipChangeListeners.isEmpty()) { |
| listener.close(); |
| listener = null; |
| return submit(new AtomixLeaderElectorCommands.Unlisten()); |
| } |
| return CompletableFuture.completedFuture(null); |
| } |
| } |