JSon schema and Inheritance
OK, well, I am the author of both:
- the current JSON Schema validation spec;
- and the Java library which is the most used for JSON Schema validation in Java today: json-schema-validator.
So I can answer your question, and the basic answer is no.
Why? Because there is no such thing as schema inheritance currently defined.
When using allOf
, you require that all schemas in allOf
match; and if you are strict about what can exist in this or that JSON, you'll have added additionalProperties
to false
. As such, you cannot inherit.
The real solution is a mechanism I proposed for draft v5: the $merge
and $patch
keywords. These would allow to patch schemas with either of RFC 7386 or RFC 6902 (see here for more info) and indeed implement schema inheritance.
In short:
- if you set
additionalProperties
tofalse
, and your basic JSON is an object, you won't be able to define additional object members; - with these two new keywords, you can.
"jsonschema2pojo" project contains notations for this purpose.
On the JSON schema, just include something like this;
"extendsJavaClass" : "com.somecompany.SomeBaseClass",
i.e.
{
"title": "....",
"description": "....",
"type": "object",
"extendsJavaClass" : "com.somecompany.SomeBaseClass",
"properties": {
"...": {
"items": {
"$ref": "#/definitions/...."
},
"type": "array"
}
.......
}
then the class generated by the project will have its "extends" clause as;
/**
* ...
* <p>
* ...
*
*/
@JsonInclude(JsonInclude.Include.NON_NULL)
@JsonPropertyOrder({
...
})
public class MyNewClass
extends SomeBaseClass
{
...
}
Also you can search for similar notations in here.
PS: Theese notations are not "standard JSON schema constructs". They are added for the sake of "just doing it" until a standard way of doing it is possible.
Hope it helps..