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.cassandra.service.accord.fastpath;
  
  import java.util.Map;
  import java.util.Set;
  
  import com.google.common.collect.ImmutableMap;
  
  import accord.local.Node;
  import accord.topology.Shard;
  import accord.utils.ArrayBuffers;
  import accord.utils.Invariants;
  import accord.utils.SortedArrays.SortedArrayList;
  
  public class SimpleFastPathStrategy implements FastPathStrategy
  {
      public static final SimpleFastPathStrategy instance = new SimpleFastPathStrategy();
  
      private static final Map<String, String> SCHEMA_PARAMS = ImmutableMap.of(Kind.KEY, Kind.SIMPLE.name());
  
      private SimpleFastPathStrategy() {}
  
      @Override
      public SortedArrayList<Node.Id> calculateFastPath(SortedArrayList<Node.Id> nodes, Set<Node.Id> unavailable, Map<Node.Id, String> dcMap)
      {
          int maxFailures = Shard.maxToleratedFailures(nodes.size());
          int discarded = 0;
  
          if (unavailable.isEmpty())
              return nodes;
  
          Object[] tmp = ArrayBuffers.cachedAny().get(nodes.size());
          for (int i=0,mi=nodes.size(); i<mi; i++)
          {
              Node.Id node = nodes.get(i);
              if (unavailable.contains(node) && discarded < maxFailures)
                  discarded++;
              else
                  tmp[i - discarded] = node;
          }
  
          Node.Id[] array = new Node.Id[nodes.size() - discarded];
          System.arraycopy(tmp, 0, array, 0, nodes.size() - discarded);
          SortedArrayList<Node.Id> fastPath = new SortedArrayList<>(array);
          Invariants.require(fastPath.size() >= Shard.slowQuorumSize(nodes.size()));
          return fastPath;
      }
  
      @Override
      public Kind kind()
      {
          return Kind.SIMPLE;
      }
  
      @Override
      public String toString()
      {
          return "simple";
      }
  
      public Map<String, String> asMap()
      {
          return SCHEMA_PARAMS;
      }
  
      @Override
      public String asCQL()
      {
          return "'simple'";
      }
  }
  