[SPARK-12857][STREAMING] Standardize "records" and "events" on "records"

[lw-lin]

What changes were proposed in this pull request?

Currently the Streaming tab in web UI uses records and events interchangeably; this PR tries to standardize them on "records".

"records" is chosen over "events" because:

• "records" is used extensively throughout the streaming documents, codes, and comments
• "events" is used only in Streaming UI related codes and comments

How was this patch tested?

• existing test suites
• manually checking on the Streaming UI tab

[lw-lin]

No public documents need to change, since we have been using the term "records" consistently.

Strings on the Streaming tab has been changed from "events" to "records".

There will be very minimum change if we also clean up the codes a little too -- only one private class, one public method in another private class, and some local variable require renaming -- so I've also done it along within this PR.

@srowen @zsxwing would you mind taking a look when you have time? Thanks!

[SparkQA]

Test build #54429 has finished for PR 12032 at commit 43e3032.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[srowen]

The other changes seem OK as they're to labels and private classes and internal code; this changes a div ID and I'm not clear if something else has to change in the code to match? like will something else fail because it doesn't find all-stream-events-timeline? I don't see any other references though.

[lw-lin]

@srowen thank you for the detailed review!

Yeah normally this requires something else to change, but GraphUIData has been implemented well enough to save the trouble. We only need to change this "all-stream-events-timeline" here, then the div ID as well as any other place referring to this div will change accordingly; please see the snapshots of the HTML source:

div as a placeholder:

then fill in that div with data:

Thanks!

[lw-lin]

@zsxwing please be aware of the changes we made here to address the problem reported in [Spark-12857] by Jacek Laskowski.

:-)

[zsxwing]

LGTM

[srowen]

Merged to master