jandex.java

        private List<org.jboss.jandex.Type> findArgumentsToSuperType(DotName currentClass, List<org.jboss.jandex.Type> args,
                DotName soughtSuperType) {
            // stop if we didn't find it
            if (currentClass.equals(OBJECT_DOT_NAME)) {
                return null;
            }

            final ClassInfo classByName = indexView.getClassByName(currentClass);

            // build a map of this classe's type params to their arguments
            Map<TypeVariable, org.jboss.jandex.Type> typeArgs = new HashMap<>();
            List<TypeVariable> typeParameters = classByName.typeParameters();
            for (int i = 0; i < typeParameters.size(); i++) {
                TypeVariable typeVariable = typeParameters.get(i);
                // default to first bound instead?
                org.jboss.jandex.Type arg;
                if (i < args.size())
                    arg = args.get(i);
                else
                    arg = typeVariable;
                typeArgs.put(typeVariable, arg);
            }

            // look at the interfaces for a direct implementation
            for (org.jboss.jandex.Type type : classByName.interfaceTypes()) {
                if (type.name().equals(soughtSuperType)) {
                    // found the type args
                    return substitute(type.asParameterizedType().arguments(), typeArgs);
                }
                // look at super-interfaces
                // FIXME: add cache to avoid visiting the same interface more than once
                List<org.jboss.jandex.Type> superArgs = findSuperArgs(type, typeArgs);
                List<org.jboss.jandex.Type> ret = findArgumentsToSuperType(type.name(), superArgs, soughtSuperType);
                if(ret != null)
                    return ret;
            }
            // look at super-type
            List<org.jboss.jandex.Type> superArgs = findSuperArgs(classByName.superClassType(), typeArgs);
            return findArgumentsToSuperType(classByName.superName(), superArgs, soughtSuperType);
        }

        private List<org.jboss.jandex.Type> findSuperArgs(org.jboss.jandex.Type superClassType,
                Map<TypeVariable, org.jboss.jandex.Type> typeArgs) {
            switch (superClassType.kind()) {
                case CLASS:
                    return Collections.emptyList();
                case PARAMETERIZED_TYPE:
                    return substitute(superClassType.asParameterizedType().arguments(), typeArgs);
                default:
                    throw new RuntimeException("Invalid supertype kind: " + superClassType);
            }
        }

        private List<org.jboss.jandex.Type> substitute(List<org.jboss.jandex.Type> types,
                Map<TypeVariable, org.jboss.jandex.Type> typeArgs){
            List<org.jboss.jandex.Type> substitutedArgs = new ArrayList<>(types);
            for (int i = 0; i < substitutedArgs.size(); i++) {
                substitutedArgs.set(i, substitute(substitutedArgs.get(i), typeArgs));
            }
            return substitutedArgs;
        }
        
        private org.jboss.jandex.Type substitute(org.jboss.jandex.Type type,
                Map<TypeVariable, org.jboss.jandex.Type> typeArgs) {
            switch (type.kind()) {
                case ARRAY:
                    ArrayType arrayType = type.asArrayType();
                    org.jboss.jandex.Type substitutedComponent = substitute(arrayType.component(), typeArgs);
                    return ArrayType.create(substitutedComponent, arrayType.dimensions());
                case TYPE_VARIABLE:
                    org.jboss.jandex.Type substitutedArgument = typeArgs.get(type.asTypeVariable());
                    return substitutedArgument != null ? substitutedArgument : type;
                case VOID:
                case PRIMITIVE:
                case CLASS:
                    return type;
                case PARAMETERIZED_TYPE:
                    ParameterizedType parameterizedType = type.asParameterizedType();
                    org.jboss.jandex.Type substitutedOwner = parameterizedType.owner() != null
                            ? substitute(parameterizedType.owner(), typeArgs)
                            : null;
                    List<org.jboss.jandex.Type> arguments = parameterizedType.arguments();
                    org.jboss.jandex.Type[] substitutedArguments = new org.jboss.jandex.Type[arguments.size()];
                    for (int i = 0; i < arguments.size(); i++) {
                        org.jboss.jandex.Type argument = arguments.get(i);
                        substitutedArguments[i] = substitute(argument, typeArgs);
                    }
                    return ParameterizedType.create(parameterizedType.name(), substitutedArguments, substitutedOwner);
                case UNRESOLVED_TYPE_VARIABLE:
                    return type;
                case WILDCARD_TYPE:
                    WildcardType wildcardType = type.asWildcardType();
                    org.jboss.jandex.Type superBound = wildcardType.superBound();
                    // do erasure to bounds
                    if (superBound != null)
                        return substitute(superBound, typeArgs);
                    return substitute(wildcardType.extendsBound(), typeArgs);
                default:
                    throw new RuntimeException("Invalid supertype kind: " + type);
            }
        }