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.distributed.util;
  
  import java.net.InetAddress;
  import java.util.Collection;
  import java.util.Iterator;
  import java.util.List;
  import java.util.concurrent.CopyOnWriteArrayList;
  
  import com.google.common.collect.Iterators;
  
  import com.datastax.driver.core.Cluster;
  import com.datastax.driver.core.Host;
  import com.datastax.driver.core.HostDistance;
  import com.datastax.driver.core.Statement;
  import com.datastax.driver.core.policies.LoadBalancingPolicy;
  
  /**
   * A CQL driver {@link LoadBalancingPolicy} that only connects to a fixed host.
   */
  public class SingleHostLoadBalancingPolicy implements LoadBalancingPolicy
  {
      private final InetAddress address;
      private Host host;
  
      public SingleHostLoadBalancingPolicy(InetAddress address)
      {
          this.address = address;
      }
  
      protected final List<Host> hosts = new CopyOnWriteArrayList<>();
  
      @Override
      public void init(Cluster cluster, Collection<Host> hosts)
      {
          host = hosts.stream()
                      .filter(h -> h.getBroadcastAddress().equals(address)).findFirst()
                      .orElseThrow(() -> new AssertionError("The host should be a contact point"));
          this.hosts.add(host);
      }
  
      @Override
      public HostDistance distance(Host host)
      {
          return HostDistance.LOCAL;
      }
  
      @Override
      public Iterator<Host> newQueryPlan(String loggedKeyspace, Statement statement)
      {
          return Iterators.singletonIterator(host);
      }
  
      @Override
      public void onAdd(Host host)
      {
          // no-op
      }
  
      @Override
      public void onUp(Host host)
      {
          // no-op
      }
  
      @Override
      public void onDown(Host host)
      {
          // no-op
      }
  
      @Override
      public void onRemove(Host host)
      {
          // no-op
      }
  
      @Override
      public void close()
      {
          // no-op
      }
  }