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.locator;
  
  import java.util.Collection;
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  
  import com.google.common.collect.Collections2;
  import org.apache.cassandra.config.DatabaseDescriptor;
  import org.apache.cassandra.dht.Range;
  import org.apache.cassandra.dht.Token;
  
  public class SystemReplicas
  {
      private static final Map<InetAddressAndPort, Replica> systemReplicas = new ConcurrentHashMap<>();
      public static final Range<Token> FULL_RANGE = new Range<>(DatabaseDescriptor.getPartitioner().getMinimumToken(),
                                                                DatabaseDescriptor.getPartitioner().getMinimumToken());
  
      private static Replica createSystemReplica(InetAddressAndPort endpoint)
      {
          return new Replica(endpoint, FULL_RANGE, true);
      }
  
      /**
       * There are a few places where a system function borrows write path functionality, but doesn't otherwise
       * fit into normal replication strategies (ie: hints and batchlog). So here we provide a replica instance
       */
      public static Replica getSystemReplica(InetAddressAndPort endpoint)
      {
          return systemReplicas.computeIfAbsent(endpoint, SystemReplicas::createSystemReplica);
      }
  
      public static EndpointsForRange getSystemReplicas(Collection<InetAddressAndPort> endpoints)
      {
          if (endpoints.isEmpty())
              return EndpointsForRange.empty(FULL_RANGE);
  
          return EndpointsForRange.copyOf(Collections2.transform(endpoints, SystemReplicas::getSystemReplica));
      }
  }
  