package storm.trident.state;
import storm.trident.operation.CombinerAggregator;
public class CombinerValueUpdater implements ValueUpdater<Object> {
Object arg;
CombinerAggregator agg;
public CombinerValueUpdater(CombinerAggregator agg, Object arg) {
this.agg = agg;
this.arg = arg;
}
@Override
public Object update(Object stored) {
if(stored==null) return arg;
else return agg.combine(stored, arg);
}
}