Java Validation constraint of enum + subtype

Question

I'm trying to improve and simplify part of my code using Java Validation constraint (@NonNull, @Min, etc...) but there is one recurrent case in my code where I can't figure out how to use constraint annotation.

Here is an example:

public class ResourceIdentifier {
    public enum ResourceType { ARTICLE, USER, COMMENT }

    private @Getter @Setter String id;
    private @Getter @Setter ResourceType type;
}

Then I would like to validate MyCommand object so resourceId is not null and resourceId.type can only be ARTICLE or COMMENT .

public class MyCommand {
    @NotNull
    @Validate(path="#resourceId.type", values={ResourceIdentifier.ResourceType.ARTICLE, ResourceIdentifier.ResourceType.COMMENT})
    private ResourceIdentifier resourceId;

    (...)
}

I believe I can achieve this with a custom constraint validation annotation and reflection.

Is there any other simple way ?

EDIT: Imagine I have 10-20 others Command class requiring the type same validation resourceId.type = {}

Answer 1

You can just use an assertion constraint (this is a method inside MyCommand ):

@AssertTrue(message="Only Comment and Article are allowed as resource type")
public boolean isResourceIdValid() {
   return this.resourceId.getType() == ResourceIdentifier.ResourceType.ARTICLE 
          || this.resourceId.getType() == ResourceIdentifier.ResourceType.COMMENT;
}