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 com.google.common.collect.Iterables;
  
  import org.apache.cassandra.config.DatabaseDescriptor;
  import org.apache.cassandra.tcm.membership.Location;
  
  public abstract class BaseProximity implements NodeProximity
  {
      public abstract int compareEndpoints(InetAddressAndPort target, Replica r1, Replica r2);
  
      /**
       * Sorts the <tt>Collection</tt> of node addresses by proximity to the given address
       * @param address the address to sort by proximity to
       * @param unsortedAddress the nodes to sort
       * @return a new sorted <tt>List</tt>
       */
      public <C extends ReplicaCollection<? extends C>> C sortedByProximity(final InetAddressAndPort address, C unsortedAddress)
      {
          return unsortedAddress.sorted((r1, r2) -> compareEndpoints(address, r1, r2));
      }
  
      public boolean isWorthMergingForRangeQuery(ReplicaCollection<?> merged, ReplicaCollection<?> l1, ReplicaCollection<?> l2)
      {
          // Querying remote DC is likely to be an order of magnitude slower than
          // querying locally, so 2 queries to local nodes is likely to still be
          // faster than 1 query involving remote ones
          boolean mergedHasRemote = hasRemoteNode(merged);
          return mergedHasRemote
                 ? hasRemoteNode(l1) || hasRemoteNode(l2)
                 : true;
      }
  
      private boolean hasRemoteNode(ReplicaCollection<?> l)
      {
          Locator locator = DatabaseDescriptor.getLocator();
          Location local = locator.local();
          return Iterables.any(l, replica -> !local.sameDatacenter(locator.location(replica.endpoint())));
      }
  }
  