EmptySeries extends ObjectSeries<T> { @Override public Series<T> filter(ValuePredicate<T> p) { return this; } EmptySeries();  EmptySeries(Class<?> nominalType); @Override int size(); @Override T get(int index); @Override void copyTo(Object[] to, int fromOffset, int toOffset, int len); @Override Series<T> filter(ValuePredicate<T> p); @Override Series<T> filter(BooleanSeries positions); @Override Series<T> sort(Comparator<? super T> comparator); @Override Series<T> materialize(); @Override Series<T> fillNulls(T value); @Override Series<T> fillNullsFromSeries(Series<? extends T> values); @Override Series<T> fillNullsBackwards(); @Override Series<T> fillNullsForward();  }
@Test public void testFilter() { Series<Object> s = new EmptySeries<>() .filter(BooleanSeries.forBooleans(true, false)); new SeriesAsserts(s).expectData(); }