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.datainteg;
  
  import java.io.IOException;
  import java.util.concurrent.CompletableFuture;
  import org.apache.bookkeeper.client.api.LedgerMetadata;
  
  /**
   * Interface for copying entries from other bookies.
   * The implementation should take care of selecting the order of the replicas
   * from which we try to read, taking into account stickiness and errors.
   * The implementation should take care of rate limiting.
   */
  public interface EntryCopier {
      /**
       * Start copying a new batch. In general, there should be a batch per ledger.
       */
      Batch newBatch(long ledgerId, LedgerMetadata metadata) throws IOException;
  
      /**
       * An interface for a batch to be copied.
       */
      interface Batch {
          /**
           * Copy an entry from a remote bookie and store it locally.
           * @return the number of bytes copied.
           */
          CompletableFuture<Long> copyFromAvailable(long entryId);
      }
  }
  