[ZEPPELIN-4512]. Move SqlSplitter from jdbc interpreter to zeppelin-interpreter

[zjffdu]

What is this PR for?

This PR move the sql split logic from jdbc interpreter to zeppelin-interpreter, so that other interpreter can reuse it. Besides that, it also fix some bugs of sql splitter, and add more unit test to verify it.

What type of PR is it?

[Bug Fix | Refactoring]

Todos

• - Task

What is the Jira issue?

• https://jira.apache.org/jira/browse/ZEPPELIN-4512

How should this be tested?

• CI pass

Screenshots (if appropriate)

Questions:

• Does the licenses files need update? No
• Is there breaking changes for older versions? No
• Does this needs documentation? No

[alexott]

The code looks good for me, but I have a general note. Some SQL dialects, also allows to use different comment characters. For example, MySQL allows to use # for single-line comments. Cassandra's SQL allows to use // for single line comments in addition to --. Maybe we can extend this code to handle an additional dialects as well? So it will be easier to reuse this split functionality in more interpreters?

[zjffdu]

Thanks for the comment @alexott
I have updated the PR to allow adding additional single line comment prefix. I am not sure whether's any other places needs to be customized for sql dialect.
SqlSplitterTest#testCustomSplitter_1 and SqlSplitterTest#testCustomSplitter_2 demonstrate that.

[alexott]

LGTM

Thank you for addition of the custom comments @zjffdu !

[zjffdu]

Thanks @alexott Will merge if no more comment