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.bookie;
  
  import org.apache.bookkeeper.bookie.CheckpointSource.Checkpoint;
  
  /**
   * The instance that is responsible for checkpointing ledger storage.
   */
  public interface Checkpointer {
  
      Checkpointer NULL = new Checkpointer(){
          @Override
          public void startCheckpoint(Checkpoint checkpoint) {
              // no-op
          }
  
          @Override
          public void start() {
              // no-op
          }
      };
  
      /**
       * Start checkpointing for a given <i>checkpoint</i> location.
       *
       * @param checkpoint the checkpoint location to checkpoint.
       */
      void startCheckpoint(Checkpoint checkpoint);
  
      void start();
  }
  