Class MessageTemplate

java.lang.Object

com.codename1.backend.messaging.MessageTemplate

public final class MessageTemplate
extends Object

Sends messages through the server's transport: what an application injects to publish, as it would Spring's KafkaTemplate or RabbitTemplate.

@Service
public class Orders {
    private final MessageTemplate messages;
    public Orders(MessageTemplate messages) { this.messages = messages; }

    @Transactional
    public void place(Order order) {
        repository.save(order);
        messages.send("orders.placed", order);
    }
}

A payload is sent as it is when it is a byte[], as UTF-8 when it is a String, and otherwise as JSON written by the codec the build generated for its type.

Inside a database transaction a send happens only if the transaction commits. The db: transport writes the message in the transaction itself; a broker transport writes it to an outbox table in the transaction and relays it after the commit, so a rollback sends nothing and a crash between the commit and the relay sends it when the server comes back. memory: holds the message until the commit.

Constructor Summary

Constructors

Constructor	Description
MessageTemplate()

Method Summary

Modifier and Type	Method	Description
void	send(Message message)	Sends message as it is.
void	send(String destination, Object payload)	Sends payload to destination.
void	send(String destination, String key, Object payload)	Sends payload to destination with an ordering key, which may be null.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

MessageTemplate

public MessageTemplate()

Method Details

send

public void send(String destination,
 Object payload)
          throws IOException

Sends payload to destination.

Throws:

IOException

send

public void send(String destination,
 String key,
 Object payload)
          throws IOException

Sends payload to destination with an ordering key, which may be null.

Throws:

IOException

send

public void send(Message message)
          throws IOException

Sends message as it is.

Throws:

IOException