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 accord.maelstrom;
  
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  
  import accord.api.Key;
  import accord.api.DataStore;
  import accord.local.CommandStore;
  import accord.local.Node;
  import accord.local.PreLoadContext;
  import accord.local.RedundantBefore;
  import accord.local.SafeCommandStore;
  import accord.primitives.Ranges;
  import accord.primitives.SyncPoint;
  import accord.utils.Timestamped;
  import accord.utils.async.AsyncResults.SettableResult;
  
  public class MaelstromStore implements DataStore
  {
      final Map<Key, Timestamped<Value>> data = new ConcurrentHashMap<>();
  
      public Value read(Key key)
      {
          Timestamped<Value> v = data.get(key);
          return v == null ? Value.EMPTY : v.data;
      }
  
      public Value get(Key key)
      {
          Timestamped<Value> v = data.get(key);
          return v == null ? Value.EMPTY : v.data;
      }
  
      static class ImmediateFetchResult extends SettableResult<Ranges> implements FetchResult
      {
          ImmediateFetchResult(Ranges ranges) { setSuccess(ranges); }
          @Override public void abort(Ranges abort) { }
      }
  
      @Override
      public FetchResult fetch(Node node, SafeCommandStore safeStore, Ranges ranges, SyncPoint syncPoint, FetchRanges callback, FetchKind kind)
      {
          return new ImmediateFetchResult(ranges);
      }
  
      @Override
      public void ensureDurable(CommandStore commandStore, Ranges ranges, RedundantBefore reportOnSuccess)
      {
          commandStore.execute((PreLoadContext.Empty)() -> "Report CommandStore Durable", safeStore -> safeStore.upsertRedundantBefore(reportOnSuccess));
      }}
  