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.stream.storage.impl.cluster;
  
  import lombok.extern.slf4j.Slf4j;
  import org.apache.bookkeeper.stream.storage.api.cluster.ClusterControllerLeader;
  import org.apache.curator.framework.CuratorFramework;
  import org.apache.curator.framework.recipes.leader.LeaderSelectorListener;
  import org.apache.curator.framework.state.ConnectionState;
  
  /**
   * This is the controller leader which watches the servers in the cluster and handles server level failures.
   *
   * <p>The controller leader is responsible for making sure all storage containers are assigned to servers, and load
   * balancing storage containers if necessary.
   */
  @Slf4j
  class ZkClusterControllerLeaderSelectorListener implements LeaderSelectorListener {
  
      private final ClusterControllerLeader controller;
  
  
      ZkClusterControllerLeaderSelectorListener(ClusterControllerLeader controller) {
          this.controller = controller;
      }
  
      @Override
      public void takeLeadership(CuratorFramework curatorFramework) throws Exception {
          controller.processAsLeader();
      }
  
      @Override
      public void stateChanged(CuratorFramework client, ConnectionState newState) {
          log.info("zookeeper connection state changed to {} for cluster controller", newState);
      }
  
  }
  