/*
* $Id$
*
* 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.protocol;
import java.net.URL;
import java.net.URLStreamHandler;
import java.net.URLStreamHandlerFactory;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.HashMap;
import org.jnode.bootlog.BootLogInstance;
import org.jnode.plugin.ConfigurationElement;
import org.jnode.plugin.Extension;
import org.jnode.plugin.ExtensionPoint;
import org.jnode.plugin.ExtensionPointListener;
import org.jnode.plugin.Plugin;
import org.jnode.plugin.PluginDescriptor;
import org.jnode.plugin.PluginException;
/**
* Plugin that installs itself as an URL Handler Factory.
* <p/>
* This plugin has a "handlers" extension point which should be used
* to register protocol handlers.
*
* @author Ewout Prangsma (epr@users.sourceforge.net)
*/
public class ProtocolHandlerFactoryPlugin extends Plugin implements
URLStreamHandlerFactory, ExtensionPointListener {
private final ExtensionPoint handlersEp;
private final HashMap<String, Class<? extends URLStreamHandler>> handlerClasses =
new HashMap<String, Class<? extends URLStreamHandler>>();
/**
* @param descriptor
*/
public ProtocolHandlerFactoryPlugin(PluginDescriptor descriptor) {
super(descriptor);
this.handlersEp = descriptor.getExtensionPoint("handlers");
reloadHandlers();
}
/**
* @see org.jnode.plugin.Plugin#startPlugin()
*/
protected void startPlugin() throws PluginException {
handlersEp.addListener(this);
try {
setHandlerFactory(this);
} catch (SecurityException ex) {
BootLogInstance.get().error("Cannot set URL Handler Factory");
}
}
/**
* @see org.jnode.plugin.Plugin#stopPlugin()
*/
protected void stopPlugin() throws PluginException {
handlersEp.removeListener(this);
try {
setHandlerFactory(null);
} catch (SecurityException ex) {
BootLogInstance.get().error("Cannot reset URL Handler Factory");
}
}
/**
* @see java.net.URLStreamHandlerFactory#createURLStreamHandler(java.lang.String)
*/
public synchronized URLStreamHandler createURLStreamHandler(String protocol) {
final Class<? extends URLStreamHandler> cls = handlerClasses.get(protocol);
if (cls != null) {
try {
return (URLStreamHandler) cls.newInstance();
} catch (InstantiationException ex) {
BootLogInstance.get().error("Cannot instantiate " + cls.getName());
} catch (IllegalAccessException ex) {
BootLogInstance.get().error("Illegal access to " + cls.getName());
}
}
return null;
}
/**
* @see org.jnode.plugin.ExtensionPointListener#extensionAdded(org.jnode.plugin.ExtensionPoint,
* org.jnode.plugin.Extension)
*/
public void extensionAdded(ExtensionPoint point, Extension extension) {
reloadHandlers();
}
/**
* @see org.jnode.plugin.ExtensionPointListener#extensionRemoved(org.jnode.plugin.ExtensionPoint,
* org.jnode.plugin.Extension)
*/
public void extensionRemoved(ExtensionPoint point, Extension extension) {
reloadHandlers();
}
private void setHandlerFactory(final URLStreamHandlerFactory factory) {
AccessController.doPrivileged(new PrivilegedAction() {
public Object run() {
URL.setURLStreamHandlerFactory(factory);
return null;
}
});
}
private synchronized void reloadHandlers() {
handlerClasses.clear();
final Extension[] exts = handlersEp.getExtensions();
final int count = exts.length;
for (int i = 0; i < count; i++) {
loadHandlers(exts[i]);
}
}
private void loadHandlers(Extension ext) {
final ConfigurationElement[] elems = ext.getConfigurationElements();
final int count = elems.length;
final ClassLoader cl = ext.getDeclaringPluginDescriptor().getPluginClassLoader();
for (int i = 0; i < count; i++) {
final ConfigurationElement elem = elems[i];
if (elem.getName().equals("handler")) {
final String protocol = elem.getAttribute("protocol");
final String className = elem.getAttribute("class");
if ((protocol != null) && (className != null)) {
try {
final Class<? extends URLStreamHandler> cls = cl.loadClass(className);
handlerClasses.put(protocol, cls);
} catch (ClassNotFoundException ex) {
BootLogInstance.get().error("Cannot load protocol handler class " + className);
}
}
}
}
}
}