org.apache.flink.api.common.functions

Interface StoppableFunction

All Known Implementing Classes:

SpoutWrapper

@PublicEvolving
public interface StoppableFunction

Must be implemented by stoppable functions, eg, source functions of streaming jobs. The method stop() will be called when the job received the STOP signal. On this signal, the source function must stop emitting new data and terminate gracefully.

Method Summary

Modifier and Type	Method and Description
void	stop() Stops the source.

Method Detail

stop

void stop()

Stops the source. In contrast to cancel() this is a request to the source function to shut down gracefully. Pending data can still be emitted and it is not required to stop immediately -- however, in the near future. The job will keep running until all emitted data is processed completely.

Most streaming sources will have a while loop inside the run() method. You need to ensure that the source will break out of this loop. This can be achieved by having a volatile field "isRunning" that is checked in the loop and that is set to false in this method.

The call to stop() should not block and not throw any exception.