UBO-122 add RateLimitedHttpClient

[yagee-de]

Link to JIRA

[fluetze]

How would one use this? Of course, I can write code to use this special kind of http client.
But enrichment resolver is already designed to use complete URIs per data source and identifier type, e.g.

MCR.MODS.EnrichmentResolver.DataSource.Scopus.doi.URI=xslStyle:import/scopus2mods,import/genre2genre:%UBO.Scopus.API.URL%abstract/doi/{0}?apikey=%UBO.Scopus.API.Key%

So, from enrichment resolver view, this is one call which hides multiple steps, xsl transformation and so on, and as first stept a http get call. Might be something else, thought.

From my point of view, it'd be easier if we had an "range limiting resolver", e.g.

MCR.MODS.EnrichmentResolver.DataSource.Scopus.doi.URI=xslStyle:import/scopus2mods,import/genre2genre:rangeLimit:scopus:%UBO.Scopus.API.URL%abstract/doi/{0}?apikey=%UBO.Scopus.API.Key%

"rangeLimit:scopus" would mean there is a RangeLimitingResolver, call and use with configuration "scopus". That configuration might be defined by a property including the range limits for Scopus.
The RangeLimitingResolver would apply that and block/async... the actual call of any URI "below".
This would fit into existing configuration with no need to rewrite Java code. We'd just had to extend the properties for all import URIs.

[fluetze]

... and I guess Bucket4J has much more features we might need, for example there might be a limit of total request per day (or even per year), and another limit per second. Web of Science is very restricting, for example.

Bucket bucket = Bucket4j.builder()
// allows 1000 tokens per 1 minute
.addLimit(Bandwidth.simple(1000, Duration.ofMinutes(1)))
// but not often then 50 tokens per 1 second
.addLimit(Bandwidth.simple(50, Duration.ofSeconds(1)))

[fluetze]

Propose to delete this branch and PR, not needed any more