code: /*
   * Copyright 2019 Mitsunori Komatsu (komamitsu)
   *
   * Licensed 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.komamitsu.fluency.fluentd.ingester.sender;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.IOException;
  import java.nio.ByteBuffer;
  import java.util.Collections;
  import java.util.List;
  
  public class MultiSender
          extends FluentdSender
  {
      private static final Logger LOG = LoggerFactory.getLogger(MultiSender.class);
      private final List<FluentdSender> senders;
  
      public MultiSender(List<FluentdSender> senders)
      {
          this(new Config(), senders);
      }
  
      public MultiSender(Config config, List<FluentdSender> senders)
      {
          super(config);
          this.senders = senders;
      }
  
      @Override
      public boolean isAvailable()
      {
          return true;
      }
  
      @Override
      protected synchronized void sendInternal(List<ByteBuffer> buffers, String ackToken)
              throws AllNodesUnavailableException
      {
          for (FluentdSender sender : senders) {
              boolean isAvailable = sender.isAvailable();
              LOG.trace("send(): sender={}, isAvailable={}", sender, isAvailable);
              if (isAvailable) {
                  try {
                      if (ackToken == null) {
                          sender.send(buffers);
                      }
                      else {
                          sender.sendWithAck(buffers, ackToken);
                      }
                      return;
                  }
                  catch (IOException e) {
                      LOG.warn("Failed to send: sender=" + sender + ". Trying to use next sender...", e);
                  }
              }
          }
          throw new AllNodesUnavailableException("All nodes are unavailable");
      }
  
      @Override
      public void close()
              throws IOException
      {
          IOException firstException = null;
          for (FluentdSender sender : senders) {
              try {
                  sender.close();
              }
              catch (IOException e) {
                  if (firstException == null) {
                      firstException = e;
                  }
              }
          }
          if (firstException != null) {
              throw firstException;
          }
      }
  
      public List<FluentdSender> getSenders()
      {
          return Collections.unmodifiableList(senders);
      }
  
      @Override
      public String toString()
      {
          return "MultiSender{" +
                  "senders=" + senders +
                  "} " + super.toString();
      }
  
      public static class AllNodesUnavailableException
              extends IOException
      {
          public AllNodesUnavailableException(String s)
          {
              super(s);
          }
      }
  
      public static class Config
              extends FluentdSender.Config
      {
      }
  }
  
  