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.net;
  
  import com.google.common.base.Preconditions;
  import org.apache.cassandra.io.IVersionedSerializer;
  import org.apache.cassandra.io.util.DataInputPlus;
  import org.apache.cassandra.io.util.DataOutputPlus;
  import org.apache.cassandra.locator.InetAddressAndPort;
  
  import java.io.IOException;
  import java.io.Serializable;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.function.BiConsumer;
  
  import static org.apache.cassandra.locator.InetAddressAndPort.Serializer.inetAddressAndPortSerializer;
  import static org.apache.cassandra.net.MessagingService.VERSION_40;
  import static org.apache.cassandra.utils.vint.VIntCoding.computeUnsignedVIntSize;
  
  /**
   * A container used to store a node -> message_id map for inter-DC write forwarding.
   * We pick one node in each external DC to forward the message to its local peers.
   *
   */
  public final class ForwardingInfo implements Serializable
  {
      private static final long serialVersionUID = 0;  // for simulator support
      final List<InetAddressAndPort> targets;
      final long[] messageIds;
  
      public ForwardingInfo(List<InetAddressAndPort> targets, long[] messageIds)
      {
          Preconditions.checkArgument(targets.size() == messageIds.length);
          this.targets = targets;
          this.messageIds = messageIds;
      }
  
      /**
       * Apply the provided consumer to all (host, message_id) pairs.
       */
      public void forEach(BiConsumer<Long, InetAddressAndPort> biConsumer)
      {
          for (int i = 0; i < messageIds.length; i++)
              biConsumer.accept(messageIds[i], targets.get(i));
      }
  
      static final IVersionedSerializer<ForwardingInfo> serializer = new IVersionedSerializer<ForwardingInfo>()
      {
          public void serialize(ForwardingInfo forwardTo, DataOutputPlus out, int version) throws IOException
          {
              assert version >= VERSION_40;
              long[] ids = forwardTo.messageIds;
              List<InetAddressAndPort> targets = forwardTo.targets;
  
              int count = ids.length;
              out.writeUnsignedVInt32(count);
  
              for (int i = 0; i < count; i++)
              {
                  inetAddressAndPortSerializer.serialize(targets.get(i), out, version);
                  out.writeUnsignedVInt(ids[i]);
              }
          }
  
          public long serializedSize(ForwardingInfo forwardTo, int version)
          {
              assert version >= VERSION_40;
              long[] ids = forwardTo.messageIds;
              List<InetAddressAndPort> targets = forwardTo.targets;
  
              int count = ids.length;
              long size = computeUnsignedVIntSize(count);
  
              for (int i = 0; i < count; i++)
              {
                  size += inetAddressAndPortSerializer.serializedSize(targets.get(i), version);
                  size += computeUnsignedVIntSize(ids[i]);
              }
  
              return size;
          }
  
          public ForwardingInfo deserialize(DataInputPlus in, int version) throws IOException
          {
              assert version >= VERSION_40;
              int count = in.readUnsignedVInt32();
  
              long[] ids = new long[count];
              List<InetAddressAndPort> targets = new ArrayList<>(count);
  
              for (int i = 0; i < count; i++)
              {
                  targets.add(inetAddressAndPortSerializer.deserialize(in, version));
                  ids[i] = in.readUnsignedVInt32();
              }
  
              return new ForwardingInfo(targets, ids);
          }
      };
  }
  