[LANG-500] ClassUtils.getAllInterfaces(...) could be more efficient

• Type: Improvement
• Status: Closed
• Priority: Trivial
• Resolution: Fixed
• Fix Version/s: 2.5
• Component/s: lang.*
• Assignee: Unassigned
• Reporter: Pino Silvaggio
• Created: 29/Apr/09 03:33
• Updated: 25/Feb/10 19:41
• Resolved: 09/Aug/09 02:45

Description

This could seem like a very minor thing but why not improve
the code once in a while...

Something like this could replace the current inefficient code:

    public static List<Class<?>> getAllInterfaces(Class<?> clazz)
    {
        if (clazz == null)
        {
            return null;
        }

        HashSet<Class<?>> interfacesSet = new HashSet<Class<?>>();
        LinkedList<Class<?>> interfacesList = new LinkedList<Class<?>>();

        getAllInterfaces(clazz, interfacesSet, interfacesList);

        return interfacesList;
    }

    private static void getAllInterfaces(
            Class<?> clazz,
            HashSet<Class<?>> interfacesSet, List<Class<?>> interfacesList)
    {
        while (clazz != null)
        {
            Class<?>[] interfaces = clazz.getInterfaces();

            for (Class<?> i : interfaces)
            {
                if (!interfacesSet.add(i))
                {
                    interfacesList.add(i);
                    getAllInterfaces(i, interfacesSet, interfacesList);
                }
            }

            clazz = clazz.getSuperclass();
        }
    }