T- The type of the elements to which this assigner assigns timestamps.
@Public @FunctionalInterface public interface TimestampAssigner<T>
TimestampAssignerassigns event time timestamps to elements. These timestamps are used by all functions that operate on event time, for example event time windows.
Timestamps can be an arbitrary
long value, but all built-in implementations represent
it as the milliseconds since the Epoch (midnight, January 1, 1970 UTC), the same way as
System.currentTimeMillis() does it.
|Modifier and Type||Field and Description|
The value that is passed to
|Modifier and Type||Method and Description|
Assigns a timestamp to an element, in milliseconds since the Epoch.
static final long NO_TIMESTAMP
extractTimestamp(T, long)when there is no previous timestamp attached to the record.
long extractTimestamp(T element, long recordTimestamp)
The method is passed the previously assigned timestamp of the element. That previous
timestamp may have been assigned from a previous assigner. If the element did not carry a
timestamp before, this value is
element- The element that the timestamp will be assigned to.
recordTimestamp- The current internal timestamp of the element, or a negative value, if no timestamp has been assigned yet.
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