Package com.sap.cds.services.messaging

Interface MessagingService

All Superinterfaces:

Service

public interface MessagingService
extends Service

Messaging service.

Field Summary

Fields

Modifier and Type	Field	Description
static final String	COMPOSITE_NAME	The name of the composite MessagingService
static final String	EVENT_MESSAGING_ERROR	The messaging error event, that allows to handle acknowledgement of a message on the messaging channel

Method Summary

Modifier and Type	Method	Description
void	emit(String topic, Map<String,Object> message)	The message Map is interpreted as data map and passed to emit(String, Map, Map).
void	emit(String topic, Map<String,Object> data, Map<String,Object> headers)	Takes a (cloudevents) message, separated into data and headers and sends it to the specified topic of this message broker.

Methods inherited from interface com.sap.cds.services.Service

after, after, after, after, before, before, before, before, emit, getName, on, on, on, on

Field Details

COMPOSITE_NAME

static final String COMPOSITE_NAME

The name of the composite MessagingService

See Also:

• Constant Field Values

EVENT_MESSAGING_ERROR

static final String EVENT_MESSAGING_ERROR

The messaging error event, that allows to handle acknowledgement of a message on the messaging channel

See Also:

• Constant Field Values

Method Details

emit

void emit(String topic,
 Map<String,Object> message)

The message Map is interpreted as data map and passed to emit(String, Map, Map). Usually this results in a final message like: {data: message}

Parameters:

topic - the topic

message - the Map to be serialized to JSON and then sent

emit

void emit(String topic,
 Map<String,Object> data,
 Map<String,Object> headers)

Takes a (cloudevents) message, separated into data and headers and sends it to the specified topic of this message broker.

Usually data and headers are combined into a final JSON string message following the rule: {...headers, data: data}. Brokers (e.g. Kafka) that natively support headers might separate headers from data

Parameters:

topic - the topic

data - the data Map

headers - the headers Map