json concepts

Exactly One

A concept, by default, requires exactly one instance in every schema. So the following concepts definition expects exactly one $service and $parameter in every schema.

CONCEPTS: service.concepts.json

{
    "$service": {
        "$parameter": "$type"
    }
}

We've already seen that following schema is valid;

SCHEMA: greeting.service.json

{
    "sayHello": {
        "name": "string"
    }
}

Missing a Concept

However following schema is not valid;

SCHEMA: greeting.service.json

{
    "sayHello": { }
}

Because it is missing a $parameter. Validation should give an error containing the missing concept name;

ERROR: 'greeting.service.json' is not valid, 'parameter' is missing.

Missing More Than One Concept

Below schema is missing both $service and a $parameter concepts;

SCHEMA: greeting.service.json

{
}

Validation should throw an error with message containing service;

ERROR: 'greeting.service.json' is not valid, 'service' is missing.

Key Literals

Just like a concept, a key literal is also required by default;

CONCEPTS: service.concepts.json

{
    "$service": {
        "response": "$responseType"
    }
}

Following schema is invalid;

SCHEMA: greeting.service.json

{
    "sayHello": { }
}

Error message should contain the missing literal;

ERROR: 'greeting.service.json' is not valid, 'response' is missing.

Null Variables

It is valid to set variables to null. Below concepts has two variables $type and $responseType.

CONCEPTS: service.concepts.json

{
    "$service": {
        "$parameter": "$type",
        "response": "$responseType"
    }
}

Below schema is valid;

SCHEMA: greeting.service.json

{
    "sayHello": { 
        "name": null,
        "response": null
    }
}

And its shadow is as follows;

SCHEMA SHADOW

{
    "service": {
        "name": "sayHello",
        "parameter": {
            "name": "name",
            "type": null
        },
        "responseType": null
    }
}