[jboss-dev] Further profling: Where should I focus?

[Bill Burke]

David M. Lloyd wrote:
> On 01/05/2010 10:40 AM, Bill Burke wrote:
>>
>> Ales Justin wrote:
>>> Perhaps this can be solved by custom (+ temp) deployer,
>>> which would create capabilities from those exports,
>>> but would just say import-all for imports.
>>>
>> No shit shirlock...Especially when thats what is being done now.
>>
>> Again, optimizing this algorithm doesn't matter if jars/directories are
>> being browsed.
> 
> What do you mean by "browsed"?  If you're going to access any file in a 
> JAR, you need to scan the (unordered) ZIP directory anyway.  Better to do 
> it one time and cache it so files can be looked up on an O(1) basis.  And 
> once you've done that, why not use that data for other purposes?
> 

A simple test of using ZipInputStream vs. URLClassLoader to find a 
resource within jacorb.jar.

ZipInputStream: 256ms.
URLClassLoader: 5ms.

URLClasLoader is obviously using some other mechanism to find things.


    public void testZipStream() throws Exception
    {
       URL url = 
Thread.currentThread().getContextClassLoader().getResource("jacorb.jar");

       ZipInputStream zis = new ZipInputStream(url.openStream());

       Map<String, ZipEntry> map = new HashMap<String, ZipEntry>();
       ZipEntry entry = null;
       while ((entry = zis.getNextEntry()) != null)
       {
          map.put(entry.getName(), entry);
       }
    }

    public void testClassLoader() throws Exception
    {
       URL[] urls = 
{Thread.currentThread().getContextClassLoader().getResource("jacorb.jar")};

       URLClassLoader cl = new URLClassLoader(urls);
       URL url = 
cl.getResource("org/jacorb/orb/portableInterceptor/RequestInterceptorIterator.class");
       System.out.println(url);
    }


--
Bill Burke
JBoss, a division of Red Hat
http://bill.burkecentral.com