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https://issues.apache.org/jira/browse/FLINK-3318?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15839833#comment-15839833
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ASF GitHub Bot commented on FLINK-3318:
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Github user mushketyk commented on the issue:
https://github.com/apache/flink/pull/2361
Hi @kl0u
Thank you for your suggestions.
I don't have a concrete solution yet, but I can try to fill the gaps in
testing and see if I can come up with a better solution.
Speaking about testing. Can you think of any other test cases that I might
need to cover?
i) Seems like a good idea. I'll add more testing and see if it can help
ii) Good point. I'll work on this.
iii) I am not sure why NFA must be changed? I think we can build NFA using
current state types by adding necessary transitions around optional states.
What do you think?
> Add support for quantifiers to CEP's pattern API
> ------------------------------------------------
>
> Key: FLINK-3318
> URL: https://issues.apache.org/jira/browse/FLINK-3318
> Project: Flink
> Issue Type: Improvement
> Components: CEP
> Affects Versions: 1.0.0
> Reporter: Till Rohrmann
> Assignee: Ivan Mushketyk
> Priority: Minor
>
> It would be a good addition to extend the pattern API to support quantifiers
> known from regular expressions (e.g. Kleene star, ?, +, or count bounds).
> This would considerably enrich the set of supported patterns.
> Implementing the count bounds could be done by unrolling the pattern state.
> In order to support the Kleene star operator, the {{NFACompiler}} has to be
> extended to insert epsilon-transition between a Kleene start state and the
> succeeding pattern state. In order to support {{?}}, one could insert two
> paths from the preceding state, one which accepts the event and another which
> directly goes into the next pattern state.
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