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.api.cluster;
  
  import java.util.Optional;
  import java.util.concurrent.Executor;
  import java.util.function.Consumer;
  import org.apache.bookkeeper.stream.proto.cluster.ClusterAssignmentData;
  import org.apache.bookkeeper.stream.proto.cluster.ClusterMetadata;
  
  /**
   * Store the cluster related metadata, such as the number of storage containers, the mapping between servers
   * to storage containers.
   */
  public interface ClusterMetadataStore extends AutoCloseable {
  
  
      default boolean initializeCluster(int numStorageContainers) {
          return initializeCluster(numStorageContainers, Optional.empty());
      }
  
      /**
       * Initialize the cluster metadata with the provided <i>numStorageContainers</i>.
       *
       * @param numStorageContainers number of storage containers.
       * @param segmentStorePath segment store path
       * @return true if successfully initialized cluster, otherwise false.
       */
      boolean initializeCluster(int numStorageContainers, Optional<String> segmentStorePath);
  
      /**
       * Get the current cluster assignment data.
       *
       * @return the cluster assignment data.
       */
      ClusterAssignmentData getClusterAssignmentData();
  
      /**
       * Update the current cluster assignment data.
       *
       * @param assignmentData cluster assignment data
       */
      void updateClusterAssignmentData(ClusterAssignmentData assignmentData);
  
      /**
       * Watch the current cluster assignment data.
       *
       * @param watcher current cluster assignment data watcher
       * @param executor the executor to run the <tt>watcher</tt>
       */
      void watchClusterAssignmentData(Consumer<Void> watcher, Executor executor);
  
      /**
       * Unwatch the current cluster assignment data.
       *
       * @param watcher current cluster assignment data watcher to remove
       */
      void unwatchClusterAssignmentData(Consumer<Void> watcher);
  
      /**
       * Returns the cluster metadata presents in the system.
       *
       * @return cluster metadata.
       */
      ClusterMetadata getClusterMetadata();
  
      /**
       * Update the current cluster metadata.
       *
       * @param clusterMetadata cluster metadata to update.
       */
      void updateClusterMetadata(ClusterMetadata clusterMetadata);
  
      /**
       * Close the metadata store.
       */
      @Override
      void close();
  
  }
  