/*
* $Id$
*
* Copyright (C) 2003-2014 JNode.org
*
* 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
package org.jnode.plugin.model;
import gnu.java.security.action.GetPolicyAction;
import java.net.URL;
import java.nio.ByteBuffer;
import java.security.AccessController;
import java.security.CodeSource;
import java.security.Policy;
import java.security.ProtectionDomain;
import java.security.cert.Certificate;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import org.jnode.bootlog.BootLogInstance;
import org.jnode.plugin.PluginClassLoader;
import org.jnode.plugin.PluginDescriptor;
import org.jnode.plugin.PluginException;
import org.jnode.vm.ResourceLoader;
import org.jnode.vm.classmgr.VmClassLoader;
/**
* @author Ewout Prangsma (epr@users.sourceforge.net)
*/
final class PluginClassLoaderImpl extends ClassLoader implements PluginClassLoader {
/**
* The registry
*/
private final PluginRegistryModel registry;
/**
* The descriptor
*/
private final PluginDescriptorModel descriptor;
/**
* The plugin jar file
*/
private final PluginJar jar;
/**
* The classloaders of the prerequisite plugins
*/
private final PluginClassLoaderImpl[] prerequisiteLoaders;
/**
* Initialize this instance.
*
* @param jar
*/
public PluginClassLoaderImpl(PluginRegistryModel registry,
PluginDescriptorModel descr, PluginJar jar,
PluginClassLoaderImpl[] prerequisiteLoaders) {
this.registry = registry;
this.descriptor = descr;
this.jar = jar;
this.prerequisiteLoaders = prerequisiteLoaders;
}
/**
* Wrap this {@link ClassLoader} around the given vmClassLoader.
* Requires special permission.
*
* @param vmClassLoader
* @param registry
* @param descr
* @param jar
* @param prerequisiteLoaders
*/
protected PluginClassLoaderImpl(VmClassLoader vmClassLoader, PluginRegistryModel registry,
PluginDescriptorModel descr, PluginJar jar,
PluginClassLoaderImpl[] prerequisiteLoaders) {
super(ClassLoader.getSystemClassLoader(), vmClassLoader);
this.registry = registry;
this.descriptor = descr;
this.jar = jar;
this.prerequisiteLoaders = prerequisiteLoaders;
}
/**
* Gets the names of the classes contained in this plugin.
*
* @return
*/
public Set<String> getClassNames() {
HashSet<String> classNames = new HashSet<String>();
for (String name : jar.resourceNames()) {
if (name.endsWith(".class")) {
name = name.substring(0, name.length() - 6);
classNames.add(name.replace('/', '.'));
}
}
return classNames;
}
/**
* Gets the names of the resources contained in this plugin.
*
* @return the set of contained resources
*/
public Collection<String> getResources() {
return jar.resourceNames();
}
/**
* Finds the specified class. This method should be overridden by class
* loader implementations that follow the new delegation model for loading
* classes, and will be called by the loadClass method after checking the
* parent class loader for the requested class. The default implementation
* throws ClassNotFoundException.
*
* @param name
* @return Class
* @throws ClassNotFoundException
* @see java.lang.ClassLoader#findClass(java.lang.String)
*/
protected final Class<?> findClass(String name) throws ClassNotFoundException {
final Class<?> cls = findPluginClass(name);
if (cls != null) {
return cls;
} else {
// Not found
throw new ClassNotFoundException(name);
}
}
/**
* Finds the specified class. This method should be overridden by class
* loader implementations that follow the new delegation model for loading
* classes, and will be called by the loadClass method after checking the
* parent class loader for the requested class. The default implementation
* throws ClassNotFoundException.
*
* @param name
* @return Class The class, or null if not found.
* @see java.lang.ClassLoader#findClass(java.lang.String)
*/
private final Class<?> findPluginClass(String name) {
// Try the prerequisite loaders first
final int max = prerequisiteLoaders.length;
for (int i = 0; i < max; i++) {
final PluginClassLoaderImpl cl = prerequisiteLoaders[i];
if (cl != null) {
final Class<?> cls = cl.findPluginClass(name);
if (cls != null) {
return cls;
}
}
}
// Try the loaded classes first
final Class<?> loadedCls = findLoadedClass(name);
if (loadedCls != null) {
return loadedCls;
}
// Look for it in the fragments
ByteBuffer b = null;
FragmentDescriptorModel fragment = null;
for (FragmentDescriptorModel l : descriptor.fragments()) {
b = loadClassData(l, name);
if (b != null) {
fragment = l;
break;
}
}
// Look for it in our own jar
if (b == null) {
b = loadClassData(jar, name);
}
if (b != null) {
// We're are now going to use one of my classes,
// so make sure that my plugin has been started.
try {
startPlugin();
if (fragment != null) {
fragment.startPlugin(registry);
}
} catch (PluginException ex) {
BootLogInstance.get().error("Error starting plugin", ex);
}
// Define package (if needed)
final int lastDotIndex = name.lastIndexOf('.');
if (lastDotIndex > 0) {
String packageName = name.substring(0, lastDotIndex);
if (getPackage(packageName) == null) {
String specTitle = null;
String specVendor = null;
String specVersion = null;
String implTitle = descriptor.getName();
String implVendor = descriptor.getProviderName();
String implVersion = descriptor.getVersion().toString();
URL sealed = null;
definePackage(packageName, specTitle, specVendor,
specVersion, implTitle, implVendor, implVersion,
sealed);
}
}
final URL sourceUrl = jar.getResource(name.replace('.', '/')
+ ".class");
final CodeSource cs = new CodeSource(sourceUrl, (Certificate[]) null);
final Policy policy = (Policy) AccessController
.doPrivileged(GetPolicyAction.getInstance());
final ProtectionDomain pd = new ProtectionDomain(cs, policy
.getPermissions(cs));
final Class<?> cls = defineClass(name, b, pd);
resolveClass(cls);
return cls;
} else {
return null;
}
}
/**
* Does this classloader contain the specified class.
*
* @return boolean
*/
protected final boolean containsClass(String name) {
final String resName = name.replace('.', '/') + ".class";
if (jar.containsResource(resName)) {
return true;
}
for (ResourceLoader l : descriptor.fragments()) {
if (l.containsResource(resName)) {
return true;
}
}
return false;
}
/**
* Finds the resource with the given name. Class loader implementations
* should override this method to specify where to find resources.
*
* @param name
* @return URL
* @see java.lang.ClassLoader#findResource(java.lang.String)
*/
protected final URL findResource(String name) {
// Try the prerequisite loaders first
final int max = prerequisiteLoaders.length;
for (int i = 0; i < max; i++) {
final PluginClassLoaderImpl cl = prerequisiteLoaders[i];
if (cl != null) {
final URL url = cl.findResource(name);
if (url != null) {
return url;
}
}
}
// Try the fragments
URL url = null;
FragmentDescriptorModel fragment = null;
for (FragmentDescriptorModel f : descriptor.fragments()) {
url = f.getResource(name);
if (url != null) {
fragment = f;
break;
}
}
// Not found, try my own plugin
// System.out.println("Try resource " + name + " on " +
// jar.getDescriptor().getId());
if (url == null) {
url = jar.getResource(name);
}
if (url != null) {
try {
startPlugin();
if (fragment != null) {
fragment.startPlugin(registry);
}
} catch (PluginException ex) {
BootLogInstance.get().error("Cannot start plugin", ex);
}
}
return url;
}
public Enumeration<?> getResources(String name) {
System.err.println("getResources " + name);
final List<URL> urls = new ArrayList<URL>();
//
// Try the prerequisite loaders first
final int max = prerequisiteLoaders.length;
for (int i = 0; i < max; i++) {
final PluginClassLoaderImpl cl = prerequisiteLoaders[i];
if (cl != null) {
final URL url = cl.findResource(name);
if (url != null) {
System.err.println("adding " + url);
if (!urls.contains(url))
urls.add(url);
}
}
}
// Try the fragments
URL url = null;
for (FragmentDescriptorModel fragment : descriptor.fragments()) {
url = fragment.getResource(name);
if (url != null) {
try {
startPlugin();
fragment.startPlugin(registry);
} catch (PluginException ex) {
BootLogInstance.get().error("Cannot start plugin", ex);
}
System.err.println("adding " + url);
if (!urls.contains(url))
urls.add(url);
}
}
// Not found, try my own plugin
// System.out.println("Try resource " + name + " on " +
// jar.getDescriptor().getId());
url = jar.getResource(name);
if (url != null) {
try {
startPlugin();
} catch (PluginException ex) {
BootLogInstance.get().error("Cannot start plugin", ex);
}
System.err.println("adding " + url);
if (!urls.contains(url))
urls.add(url);
}
//
return new Enumeration<URL>() {
private Iterator<URL> it = urls.iterator();
public boolean hasMoreElements() {
return it.hasNext();
}
public URL nextElement() {
return it.next();
}
};
}
/**
* Try to load the data of a class with a given name.
*
* @param name
* @return The loaded class data or null if not found.
*/
private final ByteBuffer loadClassData(ResourceLoader loader, String name) {
return loader.getResourceAsBuffer(name.replace('.', '/') + ".class");
}
/**
* Make sure that the plugin gets started. This method ensures that this
* classloader can be used to start the plugin.
*/
private final void startPlugin() throws PluginException {
descriptor.startPlugin(registry);
}
/**
* @see org.jnode.plugin.PluginClassLoader#getDeclaringPluginDescriptor()
*/
public PluginDescriptor getDeclaringPluginDescriptor() {
return descriptor;
}
public String toString() {
return getClass().getName() + '(' + getDeclaringPluginDescriptor().getId() + ')';
}
}