}
    }

    private static <T> T cache(ModelCache cache, Source source, String tag, Callable<T> supplier) {
        Supplier<T> s = asSupplier(supplier);
        if (cache == null) {
            return s.get();
        } else {
            return cache.computeIfAbsent(source, tag, s);
        }
    }

    private static <T> Supplier<T> asSupplier(Callable<T> supplier) {

                ModelSource source = toSource(resolver.resolveModel(p));
                if (p.getDelegate() != parent) {
                    modified.set(p.getDelegate());
                }
                return source;
            } catch (UnresolvableModelException e) {

        }
    }

    private void validate20RawResources(
            ModelProblemCollector problems, List<Resource> resources, String prefix, ModelBuilderRequest request) {
        Severity errOn30 = getSeverity(request, ModelBuilderRequest.VALIDATION_LEVEL_MAVEN_3_0);

        for (Resource resource : resources) {
            validateStringNotEmpty(
                    prefix,
                    "directory",