add caching to JsonRef.fromURI

[raimohanska]

I found out that by caching the results of JsonRef.fromURI, I can get almost 10x performance boost in the JSON Schema validation in my application. Maybe consider including the optimization into json-schema-core?

[huggsboson]

seems super useful. I'm a bit hesitant about the static, I'm looking to see if there's a place that does all this resolving where we can put a cache instead of using a static.

[raimohanska]

Sounds great! A global static cache may in fact cause a mem leak in some cases.

[huggsboson]

I probably won't get time to do it. Any chance you can take a look? Seems like a good change and I don't want to lose it because I'm swamped.

[Capstan]

Looking at the calls to fromURI, it is called in a bunch of places just within the java-json-tools repos, and likely external libraries. I think the best we could do within compatibility is provide a public static field which fromURI called, which allowed for replacing with an alternate cache mechanism, so clients could fiddle with the cache parameters. But it'd still be global, and clients might fight over it.

A more invasive deprecation of the static fromURI and replacing it with a URI factory that we then have to provide to all the places where fromURI is currently called might be suitable for a larger contribution (and a version bump).