|
|
@Override
public final Watermark getCurrentWatermark() {
// this guarantees that the watermark never goes backwards.
long potentialWM = currentMaxTimestamp - maxOutOfOrderness;
if (potentialWM >= lastEmittedWatermark) { //currentMaxTimestamp 这个已经是最大的了，单调递增，为什么这个还需判断
lastEmittedWatermark = potentialWM;
}
return new Watermark(lastEmittedWatermark);
}
@Override
public final long extractTimestamp(T element, long previousElementTimestamp) {
long timestamp = extractTimestamp(element);
if (timestamp > currentMaxTimestamp) {
currentMaxTimestamp = timestamp;
}
return timestamp;
}
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Locked
