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Posted to user@flink.apache.org by bupt_ljy <bu...@163.com> on 2019/02/15 08:10:48 UTC

[flink-cep] - What is the difference between GroupPattern and Pattern?

Hi, all
  I notice that we have GroupPattern, which is subclass of Pattern in flink-cep module. I’m not very sure about the meaning of GroupPattern and its necessity. I will appreciate if anyone can list some examples for me to help understand this?


  Thanks!




Best Regards,
Jiayi Liao

Re: [flink-cep] - What is the difference between GroupPattern and Pattern?

Posted by Dian Fu <di...@gmail.com>.

Hi Jiayi,

GroupPattern is used to support patterns like this: A (B C) {3} D. The sub-group (B C) is considered as a GroupPattern. Without it, it's impossible to support patterns like that. You can refer to the GroupITCase for more information.

Regards,
Dian

> 在 2019年2月15日，下午4:10，bupt_ljy <bu...@163.com> 写道：
> 
> Hi, all
>     I notice that we have GroupPattern, which is subclass of Pattern in flink-cep module. I’m not very sure about the meaning of GroupPattern and its necessity. I will appreciate if anyone can list some examples for me to help understand this?
> 
>     Thanks!
> 
> 
> Best Regards,
> Jiayi Liao