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From "Pino Silvaggio (JIRA)" <j...@apache.org>
Subject [jira] Updated: (LANG-500) ClassUtils.getAllInterfaces(...) could be more efficient
Date Tue, 05 May 2009 15:14:30 GMT

     [ https://issues.apache.org/jira/browse/LANG-500?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Pino Silvaggio updated LANG-500:
--------------------------------

    Attachment: patch-ClassUtils-02.txt
                patch-ClassUtils-01.txt

Patch 01 is my original version where I use an HashSet and a List.

Patch 02 uses a LinkedHashSet where a List is constructed on the return.

They are both good.

02 is a bit more memory efficient and theoretically slower (negligible) O(2N) = O(N).
01 is O(N).


> ClassUtils.getAllInterfaces(...) could be more efficient
> --------------------------------------------------------
>
>                 Key: LANG-500
>                 URL: https://issues.apache.org/jira/browse/LANG-500
>             Project: Commons Lang
>          Issue Type: Improvement
>    Affects Versions: 3.x
>            Reporter: Pino Silvaggio
>            Priority: Trivial
>         Attachments: patch-ClassUtils-01.txt, patch-ClassUtils-02.txt
>
>
> 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:
> {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();
>         }
>     }
> {code}

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