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From Kostas Kloudas <k.klou...@data-artisans.com>
Subject Re: Custom Trigger Implementation
Date Mon, 25 Apr 2016 09:52:17 GMT
Hi Piyush,

In the onElement function, you register a timer every time you receive an element. 

When the next watermark arrives, in the flag==false case, this will lead to every element

adding a timer for its timestamp+60000ms. The same for flag==true case, with 20000ms interval.

What you can try is to set only once, at the first element the initial trigger for 60 sec,
and then 
just set all the rest in the on the onEventTime with 20 sec.

To have a look at a custom trigger you can look at here:
https://github.com/kl0u/flink-examples/blob/master/src/main/java/com/dataartisans/flinksolo/beam_comparison/customTriggers/EventTimeTriggerWithEarlyAndLateFiring.java
<https://github.com/kl0u/flink-examples/blob/master/src/main/java/com/dataartisans/flinksolo/beam_comparison/customTriggers/EventTimeTriggerWithEarlyAndLateFiring.java>

I hope this helped.
Let me know if you need any help.

Kostas

> On Apr 25, 2016, at 11:22 AM, Piyush Shrivastava <piyushjoy@yahoo.co.in> wrote:
> 
> Hi all,
> I want to implement a custom Trigger which fired a GlobalWindow in 1 minute for the first
time and every 20 seconds after that.
> I believe I cannot get this logic right in the implementation of my custom Trigger. Please
help me with this.
> 
> Here is the code of my custom Trigger:
> 
> public class TradeTrigger<W extends Window> extends Trigger<Object, W> {
> 
>     /**
>      * 
>      */
>     private static final long serialVersionUID = 1L;
>       
>     private TradeTrigger() {
>     }
>     
>     @Override
>     public TriggerResult onElement(
>             Object element,
>             long timestamp,
>             W window,
>             org.apache.flink.streaming.api.windowing.triggers.Trigger.TriggerContext
ctx)
>             throws Exception {
>         
>         ctx.registerEventTimeTimer(timestamp);
>         return TriggerResult.CONTINUE;
>         
>     }
> 
>     @Override
>     public TriggerResult onEventTime(
>             long timestamp,
>             W window,
>             org.apache.flink.streaming.api.windowing.triggers.Trigger.TriggerContext
ctx)
>             throws Exception {
>     
>     ValueState<Boolean> state = ctx.getPartitionedState(new ValueStateDescriptor<Boolean>("flag",
Boolean.TYPE, false));
>         
>         if(state.value()==false){
>             ctx.registerEventTimeTimer(timestamp+60000);
>             state.update(true);
>             return TriggerResult.FIRE;
>         }else{
>             System.out.println(""+state.value());
>             ctx.registerEventTimeTimer(timestamp+20000);
>             return TriggerResult.FIRE;
>         }
>     }
> 
>     @Override
>     public TriggerResult onProcessingTime(
>             long arg0,
>             W arg1,
>             org.apache.flink.streaming.api.windowing.triggers.Trigger.TriggerContext
arg2)
>             throws Exception {
>         // TODO Auto-generated method stub
>         return TriggerResult.CONTINUE;
>     }
>     
>      
>     public static <W extends Window> TradeTrigger<W> of() {
>         return new TradeTrigger<>();
>     }
> 
>     
> }
>  
> Thanks and Regards,
> Piyush Shrivastava <mailto:piyush@webograffiti.com>
> 
> http://webograffiti.com <http://webograffiti.com/>


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