Hi Zhen Li, As far as I know that is not possible. For such custom handling I would recommend having a look at ProcessFunction[1], where you have access to timers and state.
Best, Dawid [1] https://ci.apache.org/projects/flink/flink-docs-release-1.6/dev/stream/operators/process_function.html#process-function-low-level-operations On 17/10/2018 14:18, Ahmad Hassan wrote: > Hi Niels, > > Can we distinguish within apply function of 'RichWindowFunction' > whether it was called due to onElement trigger call or > onProcessingtime trigger call of a custom Trigger ? > > Thanks! > > On Wed, 17 Oct 2018 at 12:51, Niels van Kaam <ni...@vankaam.net > <mailto:ni...@vankaam.net>> wrote: > > Hi Zhen Li, > > You can control when a windowed stream emits data with "Triggers". > See: > > https://ci.apache.org/projects/flink/flink-docs-stable/dev/stream/operators/windows.html#triggers > > Flink comes with a couple of default triggers, but you can also > create your own by implementing > > https://ci.apache.org/projects/flink/flink-docs-stable/api/java/org/apache/flink/streaming/api/windowing/triggers/Trigger.html. > > Note that this does not change the window, but just causes the > windowedstream to emit intermediate results to the next operator. > > Does this answer your question? > > Cheers, > Niels > > On Wed, Oct 17, 2018 at 12:34 PM zhen li <lizhenm...@hotmail.com > <mailto:lizhenm...@hotmail.com>> wrote: > > Hi all: > How can I trigger the window manually in fold operator or > incremental aggregation? For example, when some conditions is > meet，althouth the count window or time window is not reach >
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