content: /**
   * Licensed 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.aurora.scheduler.storage;
  
  import java.util.stream.Stream;
  
  import org.apache.aurora.gen.storage.Op;
  import org.apache.aurora.gen.storage.Snapshot;
  import org.apache.aurora.scheduler.storage.Storage.StoreProvider;
  
  /**
   * Logic to convert storage contents into a snapshot, and a snapshot into a stream of storage
   * operations.
   */
  public interface Snapshotter {
  
    /**
     * Creates a snapshot from the contents of storage.
     *
     * @param stores stores to create a snapshot from.
     * @return A snapshot that can be used to recover storage.
     */
    Snapshot from(StoreProvider stores);
  
    /**
     * Converts a snapshot into an equivalent linear stream of storage operations.
     *
     * @param snapshot A snapshot created by {@link #from(StoreProvider)}.
     * @return a stream of operations representing the contents of the snapshot.
     */
    Stream<Op> asStream(Snapshot snapshot);
  }
  