Ability to use an opaque namespace?

[bpfoster]

First I must say that after experimenting with other JSON libraries I am thoroughly impressed with this project, and thank you for it. It's simple to use and works great.

Is there a way that I'm missing, or do you have any thoughts on having an opaque namespace for schemas? I hate to talk to generics, so here's the specific use case -
Our schemas $ref each other with relative links - in this case all sit inside a folder. That folder is packaged inside the jar. I then create the factory and set the namespace similar to:

new JsonSchemaFactory.Builder().setNamespace(getClass().getResource("/schemas/").toURI().toASCIIString()).build();

Unfortunately, during validation this fails, because of the line in SchemaRegistry.get():

realURI = namespace.resolve(uri).normalize();

Because namespace is an opaque URI in this case (jar:file:/<path>!/schemas/), the Java URI API simply returns the value of the uri parameter.

A simple hack I've done to get around it is to change SchemaRegistry and basically concat namespace + uri, but I wanted to see if there was a more elegant way to do this, or a reason why not.

Thanks for the feedback.

[fge]

Hello,

First, thank you for the appreciative comments!

There is a hack in the code, in JsonRef, so as to deal specifically with jar URIs, so it seems it is not plugged where you expect. Hmm. I'll have to devise a test.

I have two questions:

1. how do you define an opaque URI? I have always had trouble with that;
2. is your jar in the classpath? If yes, can't you use:

// Note the final /
new JsonSchemaFactory.Builder().setNamespace("resource:/base/path/to/schemas/")

?

[bpfoster]

Aha! - I knew I had to be missing something stupid simple. Yes, using a resource:/path/to/schemas/ namespace works perfectly for this! Thank you!

I will admit that the idea of an opaque URI was new to me when starting this, so I have to rely on the Javadoc:

An opaque URI is an absolute URI whose scheme-specific part does not begin with a slash character ('/')

vs a hierarchical:

A hierarchical URI is either an absolute URI whose scheme-specific part begins with a slash character, or a relative URI, that is, a URI that does not specify a scheme

So in this case we have 2 URIs: jar:file:/path/to/jarfile!/path/inside/jar/ , and resource:/path/inside/jar/. Based on the documentation, I take it to mean the scheme in the first is jar: and the second is resource:. The next character (beginning the 'scheme-specific part'), respectively, is f and /, thus making the first opaque and the second hierarchical.

Thank you so much for the quick pointer!

[fge]

Glad to know it worked!

However, I still think there is a bug. You can, indeed, do:

final JsonSchema schema = factory.fromURI("jar:file:/foo/bar.jar!/path/to/schema");

and, in this case, $ref will also work. Setting a "jar" namespace and loading a schema, however, will not.

I have to think abouti it some more.