Request: export org.everit.json.schema.{Visitor, ValidationFailureReporter}

It would be great if org.everit.json.schema.Visitor and org.everit.json.schema.ValidationFailureReporter are made public. This would allow custom schema traversals like:

        CustomFailureReporter reporter = new CustomFailureReporter(schema);
        CustomVisitor visitor = new CustomVisitor(reporter);
        visitor.visit(schema);

[erosb]

Hello @dmitry-shkolnik !

Is this a blocking issue for you or just nice-to-have? The reason why these classes are currently package-private is that they might change in upcoming releases, and we don’t want to break the backward-compatibility of the public API. They are still fairly new (introduced in last Dec, version 1.8.0), and I simply don’t feel the visitor interface mature enough yet.

Good idea anyway, the visitor pattern aims arbitary processing of the visited classes, so the library should do it too. We just need a bit better visitors for this. Maintaining the backward-compatibility with deprecated but public classes causes enough headache already, I don’t want to increase these troubles.

[daniloarcidiacono]

Hello @erosb, thanks for your suggestion. I think that if I copy the Visitor class, I also need to simulate the Schema.accept() method with a series of instanceof, like the following:

void accept(org.everit.json.schema.Schema schema, com.example.my.Visitor  visitor) {
    if (schema instanceof ArraySchema) {
        visitor.visitArraySchema(schema);
    } else if (schema instanceof BooleanSchema) {
        // and so on
    }
}

Other than that, I have some doubts about the recursion of the Visitor class, in particular for nested object properties. The method Visitor.visitObjectSchema has an interesting loop

void visitObjectSchema(ObjectSchema objectSchema) {
    //  ... omitted ...
    Map<String, Schema> propertySchemas = objectSchema.getPropertySchemas();
    if (propertySchemas != null) {
        for (Map.Entry<String, Schema> entry : propertySchemas.entrySet()) {
            visitPropertySchema(entry.getKey(), entry.getValue());
        }
     }
}

void visitPropertySchema(String properyName, Schema schema) {
}

I don’t see any further call to Schema.accept() method (for example in ObjectSchemaValidatingVisitor), so how does this algorithm dig down the object hierarchy?

Thanks