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

[bupt_ljy]

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

[Dian Fu]

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 <[hidden email]> 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