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From Jiaan Zeng <l.alle...@gmail.com>
Subject Re: how to maintain state in ProcessElement
Date Wed, 10 Jul 2013 18:01:13 GMT
By reset I mean that variable is 0 every time when onEvent() is
called. Sorry for the confusion. From the wordcount point of view, it
is correct because the "int wordCounter;" is incremented to 1 in
onEvent(). I don't understand when and where the variable is reset to
0.


On Wed, Jul 10, 2013 at 12:04 PM, Matthieu Morel <mmorel@apache.org> wrote:
>
> 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
>



-- 
Regards,
Jiaan

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