org.apache.ignite.cdc

Interface CdcConsumer

public interface CdcConsumer

Consumer of WAL data change events. This consumer will receive data change events during CdcMain application invocation. The lifecycle of the consumer is the following:

• Start of the consumer start(MetricRegistry).
• Notification of the consumer by the onEvents(Iterator) call.
• Stop of the consumer stop().

In case consumer implementation wants to user IgniteLogger, please, use, LoggerResource annotation:

 public class ChangeDataCaptureConsumer implements ChangeDataCaptureConsumer {
     @LoggerResource
     private IgniteLogger log;

     ...
 }
 

Note, consumption of the CdcEvent will be started from the last saved offset. The offset of consumptions is saved on the disk every time onEvents(Iterator) returns true.

See Also:

CdcMain, CdcEvent, CacheEntryVersion

Method Summary

Modifier and Type	Method and Description
boolean	onEvents(Iterator<CdcEvent> events) Handles entry changes events.
void	start(org.apache.ignite.internal.processors.metric.MetricRegistry mreg) Starts the consumer.
void	stop() Stops the consumer.

Method Detail

start

void start(org.apache.ignite.internal.processors.metric.MetricRegistry mreg)

Starts the consumer.

Parameters:

mreg - Metric registry for consumer specific metrics.

onEvents

boolean onEvents(Iterator<CdcEvent> events)

Handles entry changes events. If this method return true then current offset will be stored and ongoing notifications after CDC application fail/restart will be started from it.

Parameters:

events - Entry change events.

Returns:

True if current offset should be saved on the disk to continue from it in case any failures or restart.

stop

void stop()

Stops the consumer. This methods can be invoked only after start(MetricRegistry).