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https://issues.apache.org/jira/browse/FLINK-3414?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15897272#comment-15897272
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Dawid Wysakowicz commented on FLINK-3414:
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Hi [~ivan.mushketyk]
Do you still want to work on it or can I take over?
I really like your proposal for the API. I have some comments though. I would
not ommit the `where` keyword as it makes the code more readable and specify
the type in filter. So I would prefer:
{code}
pattern "start" where is[SubEvent] && _.id == 42 -> "next" where is[SubEvent]
&& _.getId() > 42
{code}
rather than
{code}
pattern[SubEvent] "start" _.id == 42 ->[SubEvent] _.getId() > 42
{code}
Also I would stick with the *within* as it betters describes the period.
I like better:
{code}
pattern "start" -> "middle" _.getName() == "error" ->> "end" _.getName() ==
"critical" within 10 seconds
{code}
> Add Scala API for CEP's pattern definition
> ------------------------------------------
>
> Key: FLINK-3414
> URL: https://issues.apache.org/jira/browse/FLINK-3414
> Project: Flink
> Issue Type: Improvement
> Components: CEP
> Affects Versions: 1.0.0
> Reporter: Till Rohrmann
> Assignee: Ivan Mushketyk
> Priority: Minor
>
> Currently, the CEP library only supports a Java API to specify complex event
> patterns. In order to make it a bit less verbose for Scala users, it would be
> nice to also add a Scala API for the CEP library.
> A Scala API would also allow to pass Scala's anonymous functions as filter
> conditions or as a select function, for example, or to use partial functions
> to distinguish between different events.
> Furthermore, the Scala API could be designed to feel a bit more like a DSL:
> {code}
> begin "start" where _.id >= 42 -> "middle_1" as classOf[Subclass] ||
> "middle_2" where _.name equals "foobar" -> "end" where x => x.id <= x.volume
> {code}
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