@Override
  public ScheduledFunction getScheduledFn() {
    return this.filterFn instanceof ScheduledFunction ? (ScheduledFunction) this.filterFn : null;
  }
The spec for an operator that filters input messages based on some conditions.

@param <M> type of input message
samza-core/src/main/java/org/apache/samza/operators/spec/FilterOperatorSpec.java