cep code

[aitozi]

Hi,

i am reading flink-cep source code based on release-1.3.2 . I cant
understand here , can anyone help me on this in NFACompiler?

private List<Tuple2&lt;IterativeCondition&lt;T>, String>>
getCurrentNotCondition() {
                        List<Tuple2&lt;IterativeCondition&lt;T>, String>> notConditions = new
ArrayList<>();

                        Pattern<T, ? extends T> previousPattern = currentPattern;
                        while (previousPattern.getPrevious() != null && (
                       
previousPattern.getPrevious().getQuantifier().hasProperty(Quantifier.QuantifierProperty.OPTIONAL)
||
                                previousPattern.getPrevious().getQuantifier().getConsumingStrategy() ==
Quantifier.ConsumingStrategy.NOT_FOLLOW)) {

                                previousPattern = previousPattern.getPrevious();

                                if (previousPattern.getQuantifier().getConsumingStrategy() ==
Quantifier.ConsumingStrategy.NOT_FOLLOW) {
                                        final IterativeCondition<T> notCondition = (IterativeCondition<T>)
previousPattern.getCondition();
                                        notConditions.add(Tuple2.of(notCondition, previousPattern.getName()));
                                }
                        }
                        return notConditions;
                }

it choose the pattern "hasProperty(Quantifier.QuantifierProperty.OPTIONAL)"
or "Quantifier.ConsumingStrategy.NOT_FOLLOW" but it just add it to
notConditions when it is "Quantifier.ConsumingStrategy.NOT_FOLLOW" is there
something wrong




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[Dawid Wysakowicz]

Hi,

It is a very low level detail of the CEP library, that should be transparent for the end-user.

However, just to clarify it a bit, it is expected. The reason behind this function is to create an optional path that bypasses all optional states. NOT_FOLLOW is treated as part of optional path, but in contrast to OPTIONAL its condition should be taken into account into the combined condition. Hope it helps.

Regards,
Dawid

> On 5 Mar 2018, at 10:42, aitozi <[hidden email]> wrote:
>
> Hi,
>
> i am reading flink-cep source code based on release-1.3.2 . I cant
> understand here , can anyone help me on this in NFACompiler?
>
> private List<Tuple2&lt;IterativeCondition&lt;T>, String>>
> getCurrentNotCondition() {
> List<Tuple2&lt;IterativeCondition&lt;T>, String>> notConditions = new
> ArrayList<>();
>
> Pattern<T, ? extends T> previousPattern = currentPattern;
> while (previousPattern.getPrevious() != null && (
>
> previousPattern.getPrevious().getQuantifier().hasProperty(Quantifier.QuantifierProperty.OPTIONAL)
> ||
> previousPattern.getPrevious().getQuantifier().getConsumingStrategy() ==
> Quantifier.ConsumingStrategy.NOT_FOLLOW)) {
>
> previousPattern = previousPattern.getPrevious();
>
> if (previousPattern.getQuantifier().getConsumingStrategy() ==
> Quantifier.ConsumingStrategy.NOT_FOLLOW) {
> final IterativeCondition<T> notCondition = (IterativeCondition<T>)
> previousPattern.getCondition();
> notConditions.add(Tuple2.of(notCondition, previousPattern.getName()));
> }
> }
> return notConditions;
> }
>
> it choose the pattern "hasProperty(Quantifier.QuantifierProperty.OPTIONAL)"
> or "Quantifier.ConsumingStrategy.NOT_FOLLOW" but it just add it to
> notConditions when it is "Quantifier.ConsumingStrategy.NOT_FOLLOW" is there
> something wrong
>
>
>
>
> --
> Sent from: http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/

[aitozi]

Then what is STOP state in NFA, i haven't seen this state in event pattern
match paper ? Does each Not pattern will be transformed to stop state?



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