incubator-s4-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Matthieu Morel <mmo...@apache.org>
Subject Re: how to maintain state in ProcessElement
Date Wed, 10 Jul 2013 16:04:00 GMT

On Jul 10, 2013, at 17:30 , Jiaan Zeng <l.allen09@gmail.com> wrote:

> Hi,
> 
> I wonder how to maintain state in ProcessElement. For example,
> 
> s4-core/src/test/java/org/apache/s4/wordcount/WordCountPE.java
> The variable "int wordCounter;" is used in onEvent() function and is
> reset to zero after the onEvent() function finishes. This is
> stateless.

I don't see where that variable is reset to 0, can you point out the code?

> 
> s4-core/src/test/java/org/apache/s4/wordcount/WordClassifierPE.java
> The variables "private int counter;" and "TreeMap<String, Integer>
> counts" are used in onEvent() function to keep total word count and
> word count for each word. This is stateful.
> 
> I am confused about such behavior of ProcessElement. How do I turn
> on/off stateless if there is such option?

You can keep state in instance variables.

Regards,

Matthieu

> 
> Thanks in advance.
> 
> --
> Regards,
> Jiaan


Mime
View raw message