[SAMZA-1351] Separate Watermark Implementation from Propagation

• Type: Task
• Status: Resolved
• Priority: Major
• Resolution: Duplicate
• Affects Version/s: 0.14.0
• Fix Version/s: 0.14.0
• Assignee: Xinyu Liu
• Reporter: Xinyu Liu
• Created: 28/Jun/17 17:51
• Updated: 21/Nov/17 19:35
• Resolved: 21/Nov/17 19:35

Description

Based on Chris's feedback, I need to separate watermark implementation with propagation mechanism. Here is the feedback:

• I expected Watermark just to be a value object but that doesn't agree with the propagate method, which looks out of place. As a user I should be able to set an arbitrary watermark. This method suggests that I must first receive a watermark then copy it. If we have the former, this looks to be unnecessary.

• We seem to be mixing two ideas here... the watermark itself with its mechanism for propagation. It would be cleaner to provide these at the fluent API level (this is how flink works) and to do the right default operation for typical operations. Ultimately the user needs to be able to override this behavior though and I'm not seeing that capability so far in the design.

Issue Links

• is depended upon by: SAMZA-1260 Support Control Messages Across Intermediate Streams