Package org.apache.flink.cep.functions

Interface TimedOutPartialMatchHandler<IN>

Type Parameters:

IN - type of input elements

All Known Implementing Classes:

PatternTimeoutFlatSelectAdapter, PatternTimeoutSelectAdapter

@PublicEvolving
public interface TimedOutPartialMatchHandler<IN>

Enables handling timed out partial matches. It shall be used in a mixin style. If you need your PatternProcessFunction to be able to handle timed out partial matches implement this interface as well. Example:

 private class MyFunction extends PatternProcessFunction<IN, OUT> implements TimedOutPartialMatchHandler<IN> {

 }
 

Method Summary

Modifier and Type	Method	Description
void	processTimedOutMatch(Map<String,List<IN>> match, PatternProcessFunction.Context ctx)	Called for every timed out partial match (due to Pattern.within(Duration)).

Method Details

processTimedOutMatch

void processTimedOutMatch(Map<String,List<IN>> match,
 PatternProcessFunction.Context ctx)
                   throws Exception

Called for every timed out partial match (due to Pattern.within(Duration)). It enables custom handling, e.g. one can emit the timed out results through a side output:

 private final OutputTag<T> timedOutPartialMatchesTag = ...

 private class MyFunction extends PatternProcessFunction<IN, OUT> implements TimedOutPartialMatchHandler<IN> {

     @Override
     public void processMatch(Map<String, List<IN>> match, Context ctx, Collector<OUT> out) throws Exception {
          ...
     }

     @Override
     void processTimedOutMatch(Map<String, List<IN>> match, PatternProcessFunction.Context ctx) throws Exception {
          ctx.output(timedOutPartialMatchesTag, match);
     }
 }
 

TimeContext.timestamp() in this case returns the minimal time in which we can say that the partial match will not become a match, which is effectively the timestamp of the first element assigned to the partial match plus the value of within.

Parameters:

match - map containing the timed out partial match. Events are identified by their names.

ctx - enables access to time features and emitting results through side outputs

Throws:

Exception - This method may throw exceptions. Throwing an exception will cause the operation to fail and may trigger recovery.