content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you 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.apache.bookkeeper.clients.impl.container;
  
  import com.google.common.annotations.VisibleForTesting;
  import com.google.common.collect.Maps;
  import java.util.concurrent.ConcurrentMap;
  import org.apache.bookkeeper.clients.impl.channel.StorageServerChannelManager;
  import org.apache.bookkeeper.clients.impl.internal.api.LocationClient;
  import org.apache.bookkeeper.common.util.OrderedScheduler;
  
  /**
   * A manager manages channels/clients to storage containers.
   */
  public class StorageContainerChannelManager implements AutoCloseable {
  
      private final StorageContainerChannelFactory factory;
      private final ConcurrentMap<Long, StorageContainerChannel> scChannels;
  
      public StorageContainerChannelManager(StorageServerChannelManager channelManager,
                                            LocationClient locationClient,
                                            OrderedScheduler scheduler) {
          this((scId) -> new StorageContainerChannel(
              scId,
              channelManager,
              locationClient,
              scheduler.chooseThread(scId)));
      }
  
      @VisibleForTesting
      StorageContainerChannelManager(StorageContainerChannelFactory factory) {
          this.factory = factory;
          this.scChannels = Maps.newConcurrentMap();
      }
  
      @VisibleForTesting
      int getNumChannels() {
          return scChannels.size();
      }
  
      /**
       * Retrieve the storage container channel for storage container {@code scId}.
       *
       * <p>This call will create the storage container channel if it doesn't exist before.
       *
       * @param scId storage container id.
       * @return storage container channel.
       */
      public StorageContainerChannel getOrCreate(long scId) {
          StorageContainerChannel scChannel = scChannels.get(scId);
          if (null == scChannel) {
              StorageContainerChannel newChannel = factory.createStorageContainerChannel(scId);
              StorageContainerChannel oldChannel = scChannels.putIfAbsent(scId, newChannel);
              if (null == oldChannel) {
                  scChannel = newChannel;
              } else {
                  scChannel = oldChannel;
              }
          }
          return scChannel;
      }
  
      /**
       * Remove the storage container channel from the channels map.
       *
       * @param scId storage container channel id.
       * @return the removed storage container channel.
       */
      public StorageContainerChannel remove(long scId) {
          return scChannels.remove(scId);
      }
  
      @Override
      public void close() throws Exception {
          scChannels.clear();
      }
  }
  