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https://issues.apache.org/jira/browse/FLINK-3318?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15405429#comment-15405429
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Ivan Mushketyk edited comment on FLINK-3318 at 8/3/16 6:44 AM:
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Hi,
Do you mean something like this:
{code:java}
Pattern.begin("start")
.oneOrMore(where(...).subtype(SubEvent.class)) // + operator
.followedBy("next").optional(where(...).subtype(...)) // ? operator
.next("end").count(1, 3).(where(...)) // count bounds operator
{code}
If no one is working on this and you like the idea, I can give it a try.
was (Author: ivan.mushketyk):
Hi,
Do you mean something like this:
Pattern.begin("start")
.oneOrMore(where(...).subtype(SubEvent.class)) // + operator
.followedBy("next").optional(where(...).subtype(...)) // ? operator
.next("end").count(1, 3).(where(...)) // count bounds operator
If no one is working on this and you like the idea, I can give it a try.
> 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
> 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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