/** * Return any {@link Meta} for this windowing scheme and the {@link Strategy}. * * @return A non-null Meta object. */ @Override public Meta getMetadata() { Meta meta = new Meta(); if (shouldMeta) { String key = getMetaKey(); if (key != null) { meta.add(key, getMetadata(metadataKeys)); } meta.merge(aggregation.getMetadata()); } return meta; }