[BEAM-7508] Expose the current key to the CombineFn

• Type: Improvement
• Status: Open
• Priority: P3
• Resolution: Unresolved
• Component/s: sdk-ideas, sdk-java-core
• Labels: Clarified
• Assignee: Unassigned
• Reporter: Luke Cwik
• Created: 07/Jun/19 16:30
• Updated: 03/Apr/21 17:30

Description

One can not currently access the key during combining. Having access to the key can be useful during various phases.

There is a less then ideal workaround where the user embeds the key within the value turning the combiner over <K, V> into a combiner over <K, <K, V>>.

 

Originally asked in https://stackoverflow.com/questions/56451796/how-can-i-access-the-key-in-subclass-of-combinerfn-when-combining-a-pcollection