Publication

Data can be published on the platform by creating a message, setting its topic and payload, then calling session.publish(...).

Messages are mutable and reusable. Create them once where possible, then update the topic and payload before each publish.

Message Types

Use the Messages factory to create messages for publication.

Message Type	Create With
SBE	Messages.sbe(...)
DTO	Messages.dto(...)
Flexible	Messages.flexible(...)
Custom	Messages.custom(...)
Raw	Messages.raw()

SBE Publication

Publish an SBE message

SbeMessage<RfqEncoder, RfqDecoder> message = Messages.sbe(RfqEncoder.class);

ExpandableArrayBuffer buffer = new ExpandableArrayBuffer();
RfqEncoder encoder = new RfqEncoder();
encoder.wrapAndApplyHeader(buffer, 0, new MessageHeaderEncoder());
encoder.instrumentId("UST-10Y");
encoder.quantity(10_000_000);

message.topic(session.getApplicationName(), "rfq", "UST-10Y");
message.payloadEncoder(encoder);

Result result = session.publish(message);

DTO Publication

Publish a DTO message

DtoMessage<PriceDto> message = Messages.dto(PriceDto.class);

PriceDto price = new PriceDto();
price.instrumentId("UST-10Y");
price.bidPrice(99.125);
price.askPrice(99.375);

message.topic(session.getApplicationName(), "price", price.instrumentId());
message.payload(price);

Result result = session.publish(message);

Flexible Publication

Publish a flexible message

FlexibleMessage<Map<String, Object>> message = Messages.flexible(Map.class);

Map<String, Object> payload = new HashMap<>();
payload.put("instrument", "UST-10Y");
payload.put("price", 99.125);

message.topic(session.getApplicationName(), "price", "UST-10Y");
message.payload(payload);

Result result = session.publish(message);

Custom Publication

Publish a custom message

CustomMessage<OrderUpdate> message = Messages.custom(OrderUpdate.class);

OrderUpdate update = new OrderUpdate();
update.setOrderId("order-1");
update.setStatus("Accepted");

message.topic(session.getApplicationName(), "order", update.getOrderId());
message.payload(update);

Result result = session.publish(message);

Raw Publication

Publish a raw message

RawMessage message = Messages.raw();

int schemaId = 100;
int templateId = 1;
DirectBuffer buffer = new UnsafeBuffer("hello raw".getBytes(StandardCharsets.UTF_8));

message.topic(schemaId, templateId, session.getApplicationName(), "raw", "item-1");
message.payload(buffer, 0, buffer.capacity());

Result result = session.publish(message);

Publish Result

The publish methods return a Result.

Result result = session.publish(message);
if (result.isFailure()) {
  log.warn("Unable to publish: {}", result);
}

Some failures are transient, for example back pressure. Other failures, such as topic errors or authorization failures, indicate a problem that should be surfaced rather than retried forever.