[FLINK-10470] Add method to check if pattern can produce empty matches

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.7.0
• Component/s: Library / CEP
• Labels: pull-request-available
• Assignee: Dawid Wysakowicz
• Reporter: Dawid Wysakowicz
• Created: 01/Oct/18 08:19
• Updated: 05/Oct/18 13:26
• Resolved: 05/Oct/18 13:26

Description

There is couple of inconsistencies how CEP library handles greedy and reluctant operators at the beginning at end of pattern. This results in subtle problems how empty matches should be generated for patterns like e.g. A? or A*?, where one is greedy and the other one is reluctant. In order to provide first version of MATCH_RECOGNIZE function we should have a possibility to disable patterns which can produce empty matches.

Issue Links

• links to: GitHub Pull Request #6781