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Posted to user@storm.apache.org by "shengyi.pan" <sh...@gmail.com> on 2014/10/24 04:08:31 UTC
Re: Implement the CombinerAggregator
you can see Storm's builtin operation Count:
https://github.com/apache/storm/blob/b2a8a77c3b307137527c706d0cd7635a6afe25bf/storm-core/src/jvm/storm/trident/operation/builtin/Count.java
it return the new object:
@Override
public Long combine(Long val1, Long val2) {
return val1 + val2;
}
2014-10-24
shengyi.pan
发件人:"Delm Schmidt" <de...@gmx.net>
发送时间:2014-10-23 21:58
主题:Implement the CombinerAggregator
收件人:"user"<us...@storm.apache.org>
抄送:
Hi guys,
maybe someone can help me out.
I'm trying to write my own CombinerAggregator. Hence I'm extending the CombinerAggregator<T> Interface but I do not know how to efficiently implement the 'T combine(T val1, T val2)' method.
Is it allowed to modify the val1 attribute and then return it or should I create a new object and combine the values inside the newly created one?