geode-core/src/main/java/org/apache/geode/internal/tcp/DirectReplySender.java

/*
 * 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.geode.internal.tcp;

import static java.util.Collections.emptySet;
import static java.util.Collections.singleton;
import static org.apache.geode.internal.Assert.assertTrue;

import java.io.IOException;
import java.io.NotSerializableException;
import java.util.ArrayList;
import java.util.List;
import java.util.Set;

import org.apache.logging.log4j.Logger;
import org.jetbrains.annotations.NotNull;

import org.apache.geode.InternalGemFireException;
import org.apache.geode.annotations.Immutable;
import org.apache.geode.distributed.internal.DMStats;
import org.apache.geode.distributed.internal.DistributionMessage;
import org.apache.geode.distributed.internal.LonerDistributionManager.DummyDMStats;
import org.apache.geode.distributed.internal.ReplySender;
import org.apache.geode.distributed.internal.membership.InternalDistributedMember;
import org.apache.geode.internal.logging.log4j.LogMarker;
import org.apache.geode.logging.internal.log4j.api.LogService;

/**
 * A reply sender which replies back directly to a dedicated socket socket.
 */
class DirectReplySender implements ReplySender {
  private static final Logger logger = LogService.getLogger();

  @Immutable
  private static final DMStats DUMMY_STATS = new DummyDMStats();

  private final @NotNull Connection connection;

  private boolean sentReply = false;

  public DirectReplySender(@NotNull Connection connection) {
    this.connection = connection;
  }

  @Override
  @NotNull
  public Set<InternalDistributedMember> putOutgoing(@NotNull final DistributionMessage msg) {
    assertTrue(!sentReply, "Trying to reply twice to a message");

    connection.getConduit().getDM().getCancelCriterion().checkCancelInProgress(null);

    if (logger.isTraceEnabled(LogMarker.DM_VERBOSE)) {
      logger.trace(LogMarker.DM_VERBOSE, "Sending a direct reply {} to {}", msg,
          connection.getRemoteAddress());
    }
    final MsgStreamer ms = (MsgStreamer) MsgStreamer.create(getConnections(), msg, false,
        DUMMY_STATS, connection.getBufferPool());
    try {
      ms.writeMessage();
      final ConnectExceptions ce = ms.getConnectExceptions();
      if (ce != null && !ce.getMembers().isEmpty()) {
        assertTrue(ce.getMembers().size() == 1);
        final InternalDistributedMember member = ce.getMembers().get(0);
        logger.warn("Failed sending a direct reply to {}", member);
        return singleton(member);
      }
      sentReply = true;
      return emptySet();
    } catch (NotSerializableException e) {
      throw new InternalGemFireException(e);
    } catch (IOException ex) {
      throw new InternalGemFireException(
          "Unknown error serializing message", ex);
    } finally {
      try {
        ms.close();
      } catch (IOException e) {
        throw new InternalGemFireException("Unknown error serializing message", e);
      }
    }

  }

  /**
   * @return a mutable {@link List} for mutation by {@link MsgStreamer} upon exception.
   */
  @NotNull
  List<Connection> getConnections() {
    final ArrayList<Connection> connections = new ArrayList<>(1);
    connections.add(connection);
    return connections;
  }

}