org.microemu.app.classloader.ExtensionsClassLoader Maven / Gradle / Ivy
/**
* MicroEmulator
* Copyright (C) 2006-2007 Bartek Teodorczyk
* Copyright (C) 2006-2007 Vlad Skarzhevskyy
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* @version $Id: ExtensionsClassLoader.java 1156 2007-04-15 19:56:04Z vlads $
*/
package org.microemu.app.classloader;
import java.io.File;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.security.AccessControlContext;
import java.security.AccessController;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import java.util.StringTokenizer;
import org.microemu.app.util.IOUtils;
import org.microemu.log.Logger;
/**
*
* Class loader for device and other Extensions
*
* @author vlads
*
*/
public class ExtensionsClassLoader extends URLClassLoader {
private final static boolean debug = false;
/* The context to be used when loading classes and resources */
private AccessControlContext acc;
public ExtensionsClassLoader(URL[] urls, ClassLoader parent) {
super(urls, parent);
acc = AccessController.getContext();
}
public void addURL(URL url) {
super.addURL(url);
}
public void addClasspath(String classpath) {
StringTokenizer st = new StringTokenizer(classpath, ";");
while (st.hasMoreTokens()) {
try {
String path = st.nextToken();
if (path.startsWith("file:")) {
addURL(new URL(path));
} else {
addURL(new URL(IOUtils.getCanonicalFileURL(new File(path))));
}
} catch (MalformedURLException e) {
throw new Error(e);
}
}
}
/**
* Finds the resource with the given name. A resource is some data (images,
* audio, text, etc) that can be accessed by class code in a way that is
* independent of the location of the code.
*
*
* The name of a resource is a '/'-separated path name that
* identifies the resource.
*
*
* Search order is reverse to standard implemenation
*
*
*
* This method will first use {@link #findResource(String)} to find the
* resource. That failing, this method will NOT invoke the parent class
* loader.
*
*
* @param name
* The resource name
*
* @return A URL object for reading the resource, or
* null if the resource could not be found or the invoker
* doesn't have adequate privileges to get the resource.
*
*/
public URL getResource(final String name) {
try {
URL url = (URL) AccessController.doPrivileged(new PrivilegedExceptionAction() {
public Object run() {
return findResource(name);
}
}, acc);
if (url != null) {
return url;
}
} catch (PrivilegedActionException e) {
if (debug) {
Logger.error("Unable to find resource " + name + " ", e);
}
}
return super.getResource(name);
}
}