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From "ASF GitHub Bot (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (FLINK-7147) Support greedy quantifier in CEP
Date Wed, 02 Aug 2017 13:58:01 GMT

    [ https://issues.apache.org/jira/browse/FLINK-7147?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16110954#comment-16110954
] 

ASF GitHub Bot commented on FLINK-7147:
---------------------------------------

Github user dianfu commented on a diff in the pull request:

    https://github.com/apache/flink/pull/4296#discussion_r130883414
  
    --- Diff: flink-libraries/flink-cep/src/main/java/org/apache/flink/cep/nfa/compiler/NFACompiler.java
---
    @@ -657,25 +663,34 @@ private boolean isPatternOptional(Pattern<T, ?> pattern) {
     				true);
     
     			IterativeCondition<T> proceedCondition = getTrueFunction();
    -			if (currentPattern.getQuantifier().isGreedy()) {
    -				proceedCondition = getGreedyCondition(proceedCondition, Lists.newArrayList(takeCondition));
    +			if (currentPattern.getQuantifier().hasProperty(Quantifier.QuantifierProperty.GREEDY))
{
    +				proceedCondition = getGreedyCondition(
    +					proceedCondition,
    +					takeCondition,
    +					ignoreCondition,
    +					followingTakeCondition);;
     			}
     			final State<T> loopingState = createState(currentPattern.getName(), State.StateType.Normal,
    -				currentPattern.getQuantifier().isGreedy());
    +				currentPattern.getQuantifier().hasProperty(Quantifier.QuantifierProperty.GREEDY));
     			loopingState.addProceed(sinkState, proceedCondition);
     			loopingState.addTake(takeCondition);
     
     			addStopStateToLooping(loopingState);
     
     			if (ignoreCondition != null) {
     				final State<T> ignoreState = createState(currentPattern.getName(), State.StateType.Normal,
    -					currentPattern.getQuantifier().isGreedy());
    +					currentPattern.getQuantifier().hasProperty(Quantifier.QuantifierProperty.GREEDY));
     				ignoreState.addTake(loopingState, takeCondition);
     				ignoreState.addIgnore(ignoreCondition);
     				loopingState.addIgnore(ignoreState, ignoreCondition);
    +				if (currentPattern.getQuantifier().hasProperty(Quantifier.QuantifierProperty.GREEDY))
{
    --- End diff --
    
    @dawidwys  Good advice. Thanks a lot :). I have updated the PR per the solution you suggested.


> Support greedy quantifier in CEP
> --------------------------------
>
>                 Key: FLINK-7147
>                 URL: https://issues.apache.org/jira/browse/FLINK-7147
>             Project: Flink
>          Issue Type: Sub-task
>          Components: CEP, Table API & SQL
>            Reporter: Dian Fu
>            Assignee: Dian Fu
>
> Greedy quantifier will try to match the token as many times as possible. For example,
for pattern {{a b* c}} (skip till next is used) and inputs {{a b1 b2 c}}, if the quantifier
for {{b}} is greedy, it will only output {{a b1 b2 c}}.



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