Replace reference object type with another schema path

[PintOfBitter]

Hello,

I am having trouble generating a specific schema. Let's say I have the following classes:

package org.example.geo:

public class Region {
    private int region_id;
    private String region_name;
}

and
package org.example.studentaffairs:

public class Student {
    private int student_id;
    private String student_name;
    private Region region;
}

What I am trying to achieve are the following schemas:
for region:

{
    "type": "object",
    "properties": {
        "region_id": {
            "type" : "int"
        },
        "region_name": {
            "type": "String"
        }
    }
}

This will be saved under org.example.geo.region
And for student:

    { 
        "type": "object",
        "properties": {
            "student_id": {
                "type" : "int"
            },
            "student_name": {
                "type": "String"
            },
            "region": {
                "type": "org.example.geo.region"
            }
        }
    }

The part I am failing to do is generating region's type as "org.example.geo.region".
Is there a way I can access the objects being generated and replace them with a reference with a path to the referenced object?

Any help or clue is greatly appreciated!

Thanks,
PoB

[CarstenWickner]

Hi @PintOfBitter,

what you're proposing is strictly speaking an invalid JSON schema. There are only a handful of supported values for the type keyword. https://json-schema.org/understanding-json-schema/reference/type
It's not meant to be overridden with custom references to external schemas. The $ref keyword supports that kind of thing.

---

Since others have asked for similar things, there is already an example for introducing external references here: ExternalRefPackageExample
If you search for it here on the repository, you'll see the few issues/discussions raised on that topic.

Your target schema file for the student would then more look like this:

{ 
    "type": "object",
    "properties": {
        "student_id": {
            "type" : "integer"
        },
        "student_name": {
            "type": "string"
        },
        "region": {
            "$ref": "./org/example/geo/region"
        }
    }
}

---

However, for completeness' sake: technically you can override anything – including the type keyword – with what I'm calling a TypeAttributeOverride.
Adapting the example from the documentation, you could do something like this (obviously with some more sophisticated logic to make it reusable):

configBuilder.forTypesInGeneral()
    .withTypeAttributeOverride((node, scope, context) -> {
            if (scope.getType().getErasedType() == Region.class) {
                node.put(context.getKeyword(SchemaKeyword.TAG_TYPE), "org.example.geo.region");
            }
    });

[PintOfBitter]

Hello @CarstenWickner,

Greatly appreciate the quick response! And thanks for pointing out the issue with changing the "type" value, this is especially helpful for someone still learning the ropes on Json schemas.

I will go over the example shared and reference external schemas through the $ref.