AsyncConnections.java

/*
 * Copyright 2016 the original author or authors.
 *
 * 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 com.lambdaworks.redis.masterslave;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;

import com.lambdaworks.redis.RedisConnectionException;
import com.lambdaworks.redis.RedisURI;
import com.lambdaworks.redis.api.StatefulRedisConnection;

/**
 * @author Mark Paluch
 */
class AsyncConnections {

    private final Map<RedisURI, CompletableFuture<StatefulRedisConnection<String, String>>> futures = new TreeMap<>(
            MasterSlaveUtils.RedisURIComparator.INSTANCE);

    public AsyncConnections() {
    }

    /**
     * Add a connection for a {@link RedisURI}
     *
     * @param redisURI
     * @param connection
     */
    public void addConnection(RedisURI redisURI, CompletableFuture<StatefulRedisConnection<String, String>> connection) {
        futures.put(redisURI, connection);
    }

    /**
     * @return the {@link Connections}.
     * @throws RedisConnectionException if no connection could be established.
     */
    public Connections get(long timeout, TimeUnit timeUnit) throws InterruptedException {

        Connections connections = new Connections();
        List<Throwable> exceptions = new CopyOnWriteArrayList<>();
        List<Future<?>> sync = new ArrayList<>(this.futures.size());

        for (Map.Entry<RedisURI, CompletableFuture<StatefulRedisConnection<String, String>>> entry : this.futures.entrySet()) {

            CompletableFuture<StatefulRedisConnection<String, String>> future = entry.getValue();

            sync.add(future.whenComplete((connection, throwable) -> {

                if (throwable != null) {
                    exceptions.add(throwable);
                } else {
                    connections.addConnection(entry.getKey(), connection);
                }
            }));
        }

        RefreshFutures.awaitAll(timeout, timeUnit, sync);

        if (connections.isEmpty() && !sync.isEmpty() && !exceptions.isEmpty()) {

            RedisConnectionException collector = new RedisConnectionException(
                    "Unable to establish a connection to Redis Cluster");
            exceptions.forEach(collector::addSuppressed);

            throw collector;
        }

        return connections;
    }
}