org.apache.samza.operators.functions

Interface TimerFunction<K,OM>

Type Parameters:

K - type of the key

OM - type of the output

public interface TimerFunction<K,OM>

Allows timer registration with a key and is invoked when the timer is fired. Key must be a unique identifier for this timer, and is provided in the callback when the timer fires.

Example of a FlatMapFunction with timer:

    public class ExampleTimerFn implements FlatMapFunction<String, String>, TimerFunction<String, String> {
      public void registerTimer(TimerRegistry timerRegistry) {
        long time = System.currentTimeMillis() + 5000; // fire after 5 sec
        timerRegistry.register("example-timer", time);
      }
      public Collection<String> apply(String s) {
        ...
      }
      public Collection<String> onTimer(String key, long timestamp) {
        // example-timer fired
        ...
      }
    }
 

Method Summary

Modifier and Type	Method and Description
java.util.Collection<OM>	onTimer(K key, long timestamp) Returns the output after the timer with key fires.
void	registerTimer(TimerRegistry<K> timerRegistry) Registers any epoch-time timers using the registry

Method Detail

registerTimer

void registerTimer(TimerRegistry<K> timerRegistry)

Registers any epoch-time timers using the registry

Parameters:

timerRegistry - a keyed TimerRegistry

onTimer

java.util.Collection<OM> onTimer(K key,
                                 long timestamp)

Returns the output after the timer with key fires.

Parameters:

key - timer key

timestamp - time of the epoch-time timer fired, in milliseconds

Returns:

Collection of output elements