ClassDocImpl getClassDoc(ClassSymbol clazz) {
        ClassDocImpl result = classMap.get(clazz);
        if (result != null) return result;
        if (isAnnotationType(clazz)) {
            result = new AnnotationTypeDocImpl(this, clazz);
        } else {
            result = new ClassDocImpl(this, clazz);
        }
        classMap.put(clazz, result);
        return result;
    }