[FLINK-12822] Add explicit transformer from SerializableOptional to Optional

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Done
• Affects Version/s: 1.9.0
• Fix Version/s: 1.9.0
• Component/s: API / Type Serialization System
• Labels: pull-request-available
• Assignee: Zili Chen
• Reporter: Zili Chen
• Created: 13/Jun/19 02:23
• Updated: 13/Jun/19 15:38
• Resolved: 13/Jun/19 15:36

Description

We introduce SerializableOptional to represent return value that of Optional and transported cross network.

The purpose is reasonable. However, a wart is inside SerializableOptional. Calling SerializableOptional#map will returns a Optional, which might surprise contributors if they want to chain operations and get a SerializableOptional as final result(to another transport maybe).

Semantically return value of SerializableOptional#map should be SerializableOptional, and for interoperation, we could introduce a SerializableOptional#toOptional which easily adapt to the correct type.

cc the original author till.rohrmann

Issue Links

• links to: GitHub Pull Request #8724