io.atomix.core.election.impl.LeaderElectorProxy.java Source code

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Here is the source code for io.atomix.core.election.impl.LeaderElectorProxy.java

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/*
 * Copyright 2016-present Open Networking Foundation
 *
 * 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 io.atomix.core.election.impl;

import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Maps;
import com.google.common.collect.Sets;
import io.atomix.core.election.AsyncLeaderElector;
import io.atomix.core.election.Leadership;
import io.atomix.core.election.LeadershipEvent;
import io.atomix.core.election.LeadershipEventListener;
import io.atomix.core.election.LeaderElector;
import io.atomix.primitive.AbstractAsyncPrimitive;
import io.atomix.primitive.PrimitiveRegistry;
import io.atomix.primitive.PrimitiveState;
import io.atomix.primitive.proxy.ProxyClient;

import java.time.Duration;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.CompletableFuture;

/**
 * Distributed resource providing the {@link AsyncLeaderElector} primitive.
 */
public class LeaderElectorProxy extends AbstractAsyncPrimitive<AsyncLeaderElector<byte[]>, LeaderElectorService>
        implements AsyncLeaderElector<byte[]>, LeaderElectorClient {

    private final Set<LeadershipEventListener<byte[]>> leadershipChangeListeners = Sets.newCopyOnWriteArraySet();
    private final Map<String, Set<LeadershipEventListener<byte[]>>> topicListeners = Maps.newConcurrentMap();

    public LeaderElectorProxy(ProxyClient<LeaderElectorService> proxy, PrimitiveRegistry registry) {
        super(proxy, registry);
    }

    @Override
    public void onLeadershipChange(String topic, Leadership<byte[]> oldLeadership,
            Leadership<byte[]> newLeadership) {
        LeadershipEvent<byte[]> event = new LeadershipEvent<byte[]>(LeadershipEvent.Type.CHANGE, topic,
                oldLeadership, newLeadership);
        leadershipChangeListeners.forEach(l -> l.event(event));
        Set<LeadershipEventListener<byte[]>> listenerSet = topicListeners.get(topic);
        if (listenerSet != null) {
            listenerSet.forEach(l -> l.event(event));
        }
    }

    @Override
    public CompletableFuture<Leadership<byte[]>> run(String topic, byte[] id) {
        return getProxyClient().applyBy(topic, service -> service.run(topic, id));
    }

    @Override
    public CompletableFuture<Void> withdraw(String topic, byte[] id) {
        return getProxyClient().acceptBy(topic, service -> service.withdraw(topic, id));
    }

    @Override
    public CompletableFuture<Boolean> anoint(String topic, byte[] id) {
        return getProxyClient().applyBy(topic, service -> service.anoint(topic, id));
    }

    @Override
    public CompletableFuture<Boolean> promote(String topic, byte[] id) {
        return getProxyClient().applyBy(topic, service -> service.promote(topic, id));
    }

    @Override
    public CompletableFuture<Void> evict(byte[] id) {
        return getProxyClient().acceptAll(service -> service.evict(id));
    }

    @Override
    public CompletableFuture<Leadership<byte[]>> getLeadership(String topic) {
        return getProxyClient().applyBy(topic, service -> service.getLeadership(topic));
    }

    @Override
    public CompletableFuture<Map<String, Leadership<byte[]>>> getLeaderships() {
        return getProxyClient().applyAll(service -> service.getLeaderships()).thenApply(leaderships -> {
            ImmutableMap.Builder<String, Leadership<byte[]>> builder = ImmutableMap.builder();
            leaderships.forEach(builder::putAll);
            return builder.build();
        });
    }

    @Override
    public synchronized CompletableFuture<Void> addListener(LeadershipEventListener<byte[]> listener) {
        leadershipChangeListeners.add(listener);
        return getProxyClient().acceptAll(service -> service.listen());
    }

    @Override
    public synchronized CompletableFuture<Void> removeListener(LeadershipEventListener<byte[]> listener) {
        if (leadershipChangeListeners.remove(listener)) {
            return getProxyClient().acceptAll(service -> service.unlisten());
        }
        return CompletableFuture.completedFuture(null);
    }

    @Override
    public synchronized CompletableFuture<Void> addListener(String topic,
            LeadershipEventListener<byte[]> listener) {
        boolean empty = topicListeners.isEmpty();
        topicListeners.compute(topic, (t, s) -> {
            if (s == null) {
                s = Sets.newCopyOnWriteArraySet();
            }
            s.add(listener);
            return s;
        });

        if (empty) {
            return getProxyClient().acceptBy(topic, service -> service.listen());
        }
        return CompletableFuture.completedFuture(null);
    }

    @Override
    public synchronized CompletableFuture<Void> removeListener(String topic,
            LeadershipEventListener<byte[]> listener) {
        topicListeners.computeIfPresent(topic, (t, s) -> {
            s.remove(listener);
            return s.size() == 0 ? null : s;
        });
        if (topicListeners.isEmpty()) {
            return getProxyClient().acceptBy(topic, service -> service.unlisten());
        }
        return CompletableFuture.completedFuture(null);
    }

    private boolean isListening() {
        return !topicListeners.isEmpty();
    }

    @Override
    public CompletableFuture<AsyncLeaderElector<byte[]>> connect() {
        return super.connect().thenRun(() -> getProxyClient().getPartitions().forEach(partition -> {
            partition.addStateChangeListener(state -> {
                if (state == PrimitiveState.CONNECTED && isListening()) {
                    partition.accept(service -> service.listen());
                }
            });
        })).thenApply(v -> this);
    }

    @Override
    public LeaderElector<byte[]> sync(Duration operationTimeout) {
        return new BlockingLeaderElector<>(this, operationTimeout.toMillis());
    }
}