KafkaTemplate

KafkaTemplate is used to send and receive messages from Kafka topics. It provides methods to send messages synchronously and asynchronously, as well as to receive messages from topics.

Registration process

Each KafkaTemplate onvocation is considered as a separate operation

Operations registration process depends on a used topic.

Registered invocations

All invocations related with send method where topic is a String, are registered as separate operations.

@Service
@RequiredArgsConstructor
public class MessagesRouter {

    private final KafkaTemplate<String, SendPublicMessageRequest> kafkaTemplate;

    public void send(SendPublicMessageRequest message) {
        kafkaTemplate.send("topic-name", message).whenComplete((_, _) -> {});
    }

}

Ignored invocations

sendDefault

All invocations related with sendDefault method are ignored - it's impossible to determine the topic for which the message is sent.

@Service
@RequiredArgsConstructor
public class MessagesRouter {

    private final KafkaTemplate<String, SendPublicMessageRequest> kafkaTemplate;

    public void send(SendPublicMessageRequest message) {
        kafkaTemplate.sendDefault(message).whenComplete((_, _) -> {});
    }

}

Non-string topic name

All invocations related with send method where topic is not a String are ignored.

This behavior will be changed in the future.

@Service
@RequiredArgsConstructor
public class MessagesRouter {

    @Value("${kafka.messages.replies.topic-name}")
    private String sendTo;

    private final KafkaTemplate<String, SendPublicMessageRequest> kafkaTemplate;

    public void send(SendPublicMessageRequest message) {
        kafkaTemplate.send(sendTo, message).whenComplete((_, _) -> {});
    }

}