addToHash(hasher, spec.getPackagePrefixes());
        addToHash(hasher, spec.getResourcePrefixes());
        addToHash(hasher, spec.getResourceNames());
        addToHash(hasher, spec.getDisallowedClassNames());
        addToHash(hasher, spec.getDisallowedPackagePrefixes());
        return hasher.hash();
    }

    private static void addToHash(Hasher hasher, Set<String> items) {
        int count = items.size();

    @Override
    public void write(Encoder encoder, FilteringClassLoader.Spec spec) throws Exception {
        encodeStrings(encoder, spec.getClassNames());
        encodeStrings(encoder, spec.getDisallowedClassNames());
        encodeStrings(encoder, spec.getPackagePrefixes());
        encodeStrings(encoder, spec.getDisallowedPackagePrefixes());
        encodeStrings(encoder, spec.getPackageNames());

            return resourceNames;
        }

        public Set<String> getClassNames() {
            return classNames;
        }

        public Set<String> getDisallowedClassNames() {
            return disallowedClassNames;
        }

        public Set<String> getDisallowedPackagePrefixes() {
            return disallowedPackagePrefixes;
        }
    }