code: /*
   * Copyright (c) 2022 Airbyte, Inc., all rights reserved.
   */
  
  package io.airbyte.integrations.destination.mqtt;
  
  import com.fasterxml.jackson.databind.JsonNode;
  import com.google.common.base.Charsets;
  import com.google.common.collect.ImmutableMap;
  import io.airbyte.commons.json.Jsons;
  import io.airbyte.integrations.BaseConnector;
  import io.airbyte.integrations.base.AirbyteMessageConsumer;
  import io.airbyte.integrations.base.Destination;
  import io.airbyte.integrations.base.IntegrationRunner;
  import io.airbyte.integrations.base.JavaBaseConstants;
  import io.airbyte.protocol.models.AirbyteConnectionStatus;
  import io.airbyte.protocol.models.AirbyteConnectionStatus.Status;
  import io.airbyte.protocol.models.AirbyteMessage;
  import io.airbyte.protocol.models.ConfiguredAirbyteCatalog;
  import java.util.UUID;
  import java.util.function.Consumer;
  import org.eclipse.paho.client.mqttv3.IMqttAsyncClient;
  import org.eclipse.paho.client.mqttv3.MqttAsyncClient;
  import org.eclipse.paho.client.mqttv3.MqttMessage;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  public class MqttDestination extends BaseConnector implements Destination {
  
    private static final Logger LOGGER = LoggerFactory.getLogger(MqttDestination.class);
  
    public static final String COLUMN_NAME_AB_ID = JavaBaseConstants.COLUMN_NAME_AB_ID;
    public static final String COLUMN_NAME_EMITTED_AT = JavaBaseConstants.COLUMN_NAME_EMITTED_AT;
    public static final String COLUMN_NAME_DATA = JavaBaseConstants.COLUMN_NAME_DATA;
    public static final String COLUMN_NAME_STREAM = "_airbyte_stream";
  
    @Override
    public AirbyteConnectionStatus check(final JsonNode config) {
      try {
        final MqttDestinationConfig mqttConfig = MqttDestinationConfig.getMqttDestinationConfig(config);
        final String testTopic = mqttConfig.getTestTopic();
        if (!testTopic.isBlank()) {
          try (final IMqttAsyncClient client = new MqttAsyncClient(mqttConfig.getServerUri(), mqttConfig.getClientId())) {
            client.connect(mqttConfig.getMqttConnectOptions()).waitForCompletion();
  
            final String key = UUID.randomUUID().toString();
            final JsonNode payload = Jsons.jsonNode(ImmutableMap.of(
                COLUMN_NAME_AB_ID, key,
                COLUMN_NAME_STREAM, "test-topic-stream",
                COLUMN_NAME_EMITTED_AT, System.currentTimeMillis(),
                COLUMN_NAME_DATA, Jsons.jsonNode(ImmutableMap.of("test-key", "test-value"))));
  
            final MqttMessage message = new MqttMessage(payload.toString().getBytes(Charsets.UTF_8));
            message.setQos(mqttConfig.getQos());
            message.setRetained(mqttConfig.isRetainedMessage());
  
            client.publish(testTopic, message).getMessage();
            client.disconnectForcibly();
  
            LOGGER.info("Successfully sent message with key '{}' to MQTT broker for topic '{}'.", key, testTopic);
          }
        }
        return new AirbyteConnectionStatus().withStatus(Status.SUCCEEDED);
      } catch (final Exception e) {
        LOGGER.error("Exception attempting to connect to the MQTT broker: ", e);
        return new AirbyteConnectionStatus()
            .withStatus(Status.FAILED)
            .withMessage("Could not connect to the MQTT broker with provided configuration. \n" + e.getMessage());
      }
    }
  
    @Override
    public AirbyteMessageConsumer getConsumer(final JsonNode config,
                                              final ConfiguredAirbyteCatalog catalog,
                                              final Consumer<AirbyteMessage> outputRecordCollector) {
      return new MqttRecordConsumer(MqttDestinationConfig.getMqttDestinationConfig(config),
          catalog,
          outputRecordCollector);
    }
  
    public static void main(final String[] args) throws Exception {
      final Destination destination = new MqttDestination();
      LOGGER.info("Starting destination: {}", MqttDestination.class);
      new IntegrationRunner(destination).run(args);
      LOGGER.info("Completed destination: {}", MqttDestination.class);
    }
  
  }
  