Inheritance & GraphQLInterface

Hey, I’ve got problem with creating some abstraction over my code and schema. What I want to achieve is, that in GraphQL Schema, “MyList” implements Interface, and I could see fields from PageableAndSortableList class only in Schema “Interface”.

@GraphQLType(name = "MyList")
public class MyGraphQLList<T> extends PageableAndSortableList {

    private List<T> pageList;
    private Order order;
    private int limit;
    private String cursor;

    @GraphQLNonNull
    public String getCursor() {
        return cursor;
    }

}

@GraphQLInterface(name = "Interface")
public abstract class PageableAndSortableList {

    protected Long total;

    protected Integer count;

    protected String next;

}

Having something like this with proper getters and setters ofc, I receive the following error on spring boot app start:

Caused by: graphql.schema.validation.InvalidSchemaException: invalid schema: object type ‘MyList_Contact’ does not implement interface ‘Interface’ because field ‘count’ is missing object type ‘MyList_Contact’ does not implement interface ‘Interface’ because field ‘next’ is missing object type ‘MyList_Contact’ does not implement interface ‘Interface’ because field ‘total’ is missing at graphql.schema.GraphQLSchema$Builder.build(GraphQLSchema.java:241) ~[graphql-java-7.0.jar:na] at graphql.schema.GraphQLSchema$Builder.build(GraphQLSchema.java:231) ~[graphql-java-7.0.jar:na] at io.leangen.graphql.GraphQLSchemaGenerator.generate(GraphQLSchemaGenerator.java:824) ~[spqr-0.9.6.jar:na] at com.example.demo.graphql.GraphQLController.<init>(GraphQLController.java:43) ~[classes/:na] at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_121] at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_121] at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_121] at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_121] at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:142) ~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE] … 20 common frames omitted

Could you help me with some solution.

[kaqqao]

I’ve just tested this, and as long as you have the getters on the abstract class, it works as expected:

@GraphQLInterface(name = "Interface")
    public static abstract class PageableAndSortableList {

        private Long total;
        private Integer count;
        private String next;

        public Long getTotal() {
            return total;
        }

        public void setTotal(Long total) {
            this.total = total;
        }

        public Integer getCount() {
            return count;
        }

        public void setCount(Integer count) {
            this.count = count;
        }

        public String getNext() {
            return next;
        }

        public void setNext(String next) {
            this.next = next;
        }
    }

The reason why it may be failing for you is that the abstract class and the implementation class are not in the same package and you didn’t set the global basePackages. If there is a finite set of base packages where all the stuff in your app that you want exposed resides, you can simply use GraphQLSchemaGenerator#withBasePackages to configure the packages.

E.g. generator.withBasePackages("com.your.company"). If possible, this is the recommended approach.

One reason why this is important is that nested classes are normally scanned for getters to expose as GraphQL fields even when they’re not annotated with @GraphQLQuery. But there is no way to know if some of the inherited getters are framework methods or default Java stuff that should’t be exposed. So, what BeanResolverBuilder does by default is filter the methods my package. If you don’t set any base packages, it only considers the package of the scanned class as acceptable (MyGraphQLList in your case). And if some super classes/interfaces are from a different package, their methods will be filtered out. This is likely what happened, so MyGraphQLList ended up without the total, count and next fields, and is thus not a valid implementation if its interface.

You can also set a separate ResolverBuilder per type, if you can’t or don’t want to set the base packages globally. E.g.

generator.withNestedResolverBuildersForType(new TypeToken<MyGraphQLList<String>>(){}.getType(), new BeanResolverBuilder("some.package"))

This way it will only use some.packge as the criteria when mapping MyGraphQLList<String> and not other types.

Unfortunately, the code will not work in your case because of a bug in the hashCode implementation in a library SPQR uses under the hood. I’ll have that fixed asap.

[daviestobialex]

@kaqqao I deeply apologize. I was using an older version of your library version 0.03 I switched to version 0.05 and it works now.