Support BCE dates in Wikibase upload

[wetneb]

The Wikibase extension does not currently let the user upload "negative" dates (in the Julian/Gregorian calendars).

The currently supported formats are documented here: https://www.wikidata.org/wiki/Wikidata:Tools/OpenRefine/Editing/Schema_alignment#Dates

Proposed solution

Introduce a new syntax for those dates. For instance -YYYY or YYYY BCE could be used. Both are supported by Wikibase's UI.

Alternatives considered

We already support setting arbitrary calendars so in theory users could just use a calendar whose origin is before the date they want to represent, but that's really complicated and Wikibase will not convert between calendars by itself.

Additional context

Requested on the mailing list:
https://groups.google.com/g/openrefine/c/nBLMNsq98k4

[wetneb]

Marking as a good first issue since this is fairly self-contained: changes should be contained to this class and its corresponding test class:
https://github.com/OpenRefine/OpenRefine/blob/master/extensions/wikidata/src/org/openrefine/wikidata/schema/WbDateConstant.java

[loulankxh]

Hi, sir. I want to have a try at this issue but I encountered a problem when I try to build, compile the wikidata extension before running the tests. The error message is "Failed to execute goal on project wikidata: Could not resolve dependencies for project org.openrefine:wikidata:jar:3.5-SNAPSHOT: org.openrefine:main:jar:tests:3.5-SNAPSHOT was not found in https://oss.sonatype.org/content/repositories/snapshots/ during a previous attempt." and the website "https://oss.sonatype.org/content/repositories/snapshots/" is permission denied. I have tried many mirrors to try to get the dependency wikidata jar, however none of them succeed for this problem. I wonder if you know some possible reasons. Thanks

[wetneb]

Hi @loulankxh, thanks for giving this a try! Yes this is a known issue about our build setup. Have you tried mvn compile test-compile?

Is this a problem you have through some IDE? On the command-line I would recommend to use the refine wrapper with refine build.

[loulankxh]

Thanks really! The problem has been solved and now I can run tests for the wikidata module successfully. I will continue to fix this issue.