/**
* Copyright (C) 2007 Aelitis, All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* AELITIS, SAS au capital de 63.529,40 euros
* 8 Allee Lenotre, La Grille Royale, 78600 Le Mesnil le Roi, France.
*
*/
package com.aelitis.azureus.launcher.classloading;
import java.io.File;
import java.lang.ref.WeakReference;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.ArrayList;
/**
* @author Aaron Grunthal
* @create 28.12.2007
*/
public class PrimaryClassloader extends URLClassLoader implements PeeringClassloader {
private final ArrayList peersLoaders = new ArrayList();
private final ClassLoader packageLoader;
private static final String packageName = PrimaryClassloader.class.getPackage().getName();
/**
* initialization path when loaded through bootstrapping
*/
private PrimaryClassloader()
{
super(generateURLs(),getSystemClassLoader().getParent());
this.packageLoader = getSystemClassLoader();
}
/**
* initialization path when loaded via
* <code>-Djava.system.class.loader=com.aelitis.azureus.launcher.classloading.PrimaryClassloader</code>
* instead of bootstrapping, has the advantage that this gets registered as system classloader
*
* @deprecated DO NOT INVOKE MANUALLY
*/
public PrimaryClassloader(ClassLoader parent)
{
super(generateURLs(),parent.getParent());
this.packageLoader = parent;
}
private static URL[] generateURLs()
{
String classpath = System.getProperty("java.class.path");
String[] paths = classpath.split(File.pathSeparator);
URL[] urls = new URL[paths.length+1];
try
{
for(int i=0;i<paths.length;i++)
{
urls[i] = new File(paths[i]).getCanonicalFile().toURI().toURL();
System.out.print(urls[i]+" ; ");
}
urls[urls.length-1] = new File(".").getCanonicalFile().toURI().toURL();
System.out.println(urls[urls.length-1]);
} catch (Exception e)
{
System.err.println("Invalid classpath detected\n");
e.printStackTrace();
System.exit(1);
}
return urls;
}
/**
* altered class lookup
* <ol>
* <li>follow normal delegation, circumventing the system classloader as we bootstraped it away</li>
* <li>OR delegate to the system classloader iff it is for classes from this package, this allows us to rebootstrap and discard other branches in the hierarchy</li>
* <li>check for loaded by peers</li>
* <li>try to load from peers</li>
* </ol>
*/
protected Class loadClass(final String name, boolean resolve) throws ClassNotFoundException {
//System.out.println(this+" loading "+name);
Class c;
try
{
if (!name.startsWith(packageName))
c = super.loadClass(name, resolve);
else
c = packageLoader.loadClass(name);
} catch (ClassNotFoundException e)
{
c = peerFindLoadedClass(name);
if (c == null)
c = peerLoadClass(name);
if (c == null)
throw e;
if (resolve)
resolveClass(c);
}
return c;
}
private Class peerFindLoadedClass(String className)
{
Class c = null;
synchronized (peersLoaders)
{
for (int i = 0; i < peersLoaders.size() && c == null; i++)
{
WeakReference ref = (WeakReference) peersLoaders.get(i);
SecondaryClassLoader loader = (SecondaryClassLoader) ref.get();
if (loader != null)
c = loader.findLoadedClassHelper(className);
else
peersLoaders.remove(i--);
}
}
return c;
}
private Class peerLoadClass(String className)
{
Class c = null;
synchronized (peersLoaders)
{
for(int i=0;i<peersLoaders.size()&&c==null;i++)
{
WeakReference ref = (WeakReference)peersLoaders.get(i);
SecondaryClassLoader loader = (SecondaryClassLoader)ref.get();
if(loader != null) // no removal here, peerFindLoadedClass should take care of that anyway
c = loader.findClassHelper(className);
}
}
return c;
}
void registerSecondaryClassloader(SecondaryClassLoader loader)
{
synchronized (peersLoaders)
{
peersLoaders.add(new WeakReference(loader));
}
}
/**
*
* @param toRun
*/
public static ClassLoader getBootstrappedLoader()
{
ClassLoader loader = ClassLoader.getSystemClassLoader();
try
{
return (ClassLoader) loader.loadClass(PrimaryClassloader.class.getName()).newInstance();
} catch (Exception e)
{
System.err.println("Could not instantiate Classloader\n");
e.printStackTrace();
System.exit(1);
return null;
}
}
}