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.distributedlog.api.subscription;
  
  import java.io.Closeable;
  import java.util.Map;
  import java.util.concurrent.CompletableFuture;
  import org.apache.distributedlog.DLSN;
  
  /**
   * Store to manage subscriptions.
   */
  public interface SubscriptionsStore extends Closeable {
  
      /**
       * Get the last committed position stored for <i>subscriberId</i>.
       *
       * @param subscriberId
       *          subscriber id
       * @return future representing last committed position.
       */
      CompletableFuture<DLSN> getLastCommitPosition(String subscriberId);
  
      /**
       * Get the last committed positions for all subscribers.
       *
       * @return future representing last committed positions for all subscribers.
       */
      CompletableFuture<Map<String, DLSN>> getLastCommitPositions();
  
      /**
       * Advance the last committed position for <i>subscriberId</i>.
       *
       * @param subscriberId
       *          subscriber id.
       * @param newPosition
       *          new committed position.
       * @return future representing advancing result.
       */
      CompletableFuture<Void> advanceCommitPosition(String subscriberId, DLSN newPosition);
  
      /**
       * Delete the subscriber <i>subscriberId</i> permanently. Once the subscriber is deleted, all the
       * data stored under this subscriber will be lost.
       * @param subscriberId subscriber id
       * @return future represent success or failure.
       * return true only if there's such subscriber and we removed it successfully.
       * return false if there's no such subscriber, or we failed to remove.
       */
      CompletableFuture<Boolean> deleteSubscriber(String subscriberId);
  
  }
  