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.bifromq.basecluster.memberlist;
  
  import org.apache.bifromq.basecluster.messenger.IRecipient;
  import org.apache.bifromq.basecluster.messenger.IRecipientSelector;
  import io.reactivex.rxjava3.core.Scheduler;
  import io.reactivex.rxjava3.disposables.Disposable;
  import java.net.InetSocketAddress;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.List;
  import java.util.stream.Collectors;
  
  public class MemberSelector implements IRecipientSelector {
      private final Disposable disposable;
      private volatile List<IRecipient> recipients = new ArrayList<>();
  
      public MemberSelector(IHostMemberList memberList, Scheduler scheduler, IHostAddressResolver addressResolver) {
          disposable = memberList.members()
              .observeOn(scheduler)
              .subscribe(members -> recipients = members.keySet()
                  .stream()
                  .map(m -> {
                      InetSocketAddress address = addressResolver.resolve(m);
                      return (IRecipient) () -> address;
                  })
                  .collect(Collectors.toList()));
      }
  
      @Override
      public Collection<? extends IRecipient> selectForSpread(int limit) {
          List<IRecipient> addresses = recipients;
          if (addresses.size() <= limit) {
              return addresses;
          }
          Collections.shuffle(addresses);
          return addresses.subList(0, limit);
      }
  
      @Override
      public int clusterSize() {
          return recipients.size();
      }
  
      public void stop() {
          disposable.dispose();
      }
  }
  