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/*****************************************************************************
* Java Plug-in Framework (JPF)
* Copyright (C) 2004-2007 Dmitry Olshansky
*
* 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
*****************************************************************************/
package org.java.plugin.standard;
import java.security.AccessController;
import java.security.PrivilegedAction;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.java.plugin.Plugin;
import org.java.plugin.PluginLifecycleException;
import org.java.plugin.PluginManager;
import org.java.plugin.registry.PluginDescriptor;
import org.java.plugin.util.ExtendedProperties;
/**
* Standard implementation of plug-in life cycle handler.
* <p>
* <b>Configuration parameters</b>
* </p>
* <p>
* This life cycle handler implementation supports following configuration
* parameters:
* <dl>
* <dt>probeParentLoaderLast</dt>
* <dd>If <code>true</code>, plug-in classloader will try loading classes from
* system (boot) classpath <b>after</b> trying to load them from plug-in
* classpath. Otherwise system classpath will be used <b>first</b>. Default
* value is <code>false</code> that corresponds to standard delegation model
* for classloaders hierarchy that corresponds to JLS.</dd>
* <dt>stickySynchronizing</dt>
* <dd>Allows advanced configuring of classloaders synchronization in
* multy-threaded environment. If <code>true</code> then class loading will
* be synchronized with initial plug-in classloader instance. Otherwise
* <code>this</code> instance will be used as synchronizing monitor. Default
* value is <code>false</code>.</dd>
* <dt>localClassLoadingOptimization</dt>
* <dd>If <code>true</code> then plug-in classloader will collect local
* packages statistics to predict class location. This allow to optimize
* class look-up procedure for classes that belong to the requested plug-in.
* Default value is <code>true</code>.</dd>
* <dt>foreignClassLoadingOptimization</dt>
* <dd>If <code>true</code> then plug-in classloader will collect statistics
* for "foreign" classes - those which belong to depending plug-ins. This
* allow to optimize class look-up procedure when enumerating depending
* plug-ins. Default value is <code>true</code>.</dd>
* </dl>
* </p>
* @version $Id: StandardPluginLifecycleHandler.java,v 1.5 2007/04/07 12:39:50 ddimon Exp $
*/
public class StandardPluginLifecycleHandler extends PluginLifecycleHandler {
private final Log log = LogFactory.getLog(getClass());
private boolean probeParentLoaderLast;
private boolean stickySynchronizing;
private boolean localClassLoadingOptimization;
private boolean foreignClassLoadingOptimization;
/**
* Creates standard implementation of plug-in class loader.
* @see org.java.plugin.standard.PluginLifecycleHandler#createPluginClassLoader(
* org.java.plugin.registry.PluginDescriptor)
*/
@Override
protected org.java.plugin.PluginClassLoader createPluginClassLoader(
final PluginDescriptor descr) {
/*StandardPluginClassLoader result = new StandardPluginClassLoader(
getPluginManager(), descr, getClass().getClassLoader());*/
StandardPluginClassLoader result = AccessController.doPrivileged(
new PrivilegedAction<StandardPluginClassLoader>() {
public StandardPluginClassLoader run() {
return new StandardPluginClassLoader(getPluginManager(), descr,
StandardPluginLifecycleHandler.this.getClass()
.getClassLoader());
}
});
result.setProbeParentLoaderLast(probeParentLoaderLast);
result.setStickySynchronizing(stickySynchronizing);
result.setLocalClassLoadingOptimization(localClassLoadingOptimization);
result.setForeignClassLoadingOptimization(
foreignClassLoadingOptimization);
return result;
}
/**
* Creates instance of plug-in class calling it's default (no-arguments)
* constructor. Class look-up is done with
* {@link PluginManager#getPluginClassLoader(PluginDescriptor) plug-in's class loader}.
* @see org.java.plugin.standard.PluginLifecycleHandler#createPluginInstance(
* org.java.plugin.registry.PluginDescriptor)
*/
@Override
protected Plugin createPluginInstance(final PluginDescriptor descr)
throws PluginLifecycleException {
String className = descr.getPluginClassName();
Class<?> pluginClass;
try {
pluginClass =
getPluginManager().getPluginClassLoader(descr).loadClass(
className);
} catch (ClassNotFoundException cnfe) {
throw new PluginLifecycleException(
StandardObjectFactory.PACKAGE_NAME,
"pluginClassNotFound", className, cnfe); //$NON-NLS-1$
}
try {
return (Plugin) pluginClass.newInstance();
} catch (InstantiationException ie) {
throw new PluginLifecycleException(
StandardObjectFactory.PACKAGE_NAME,
"pluginClassInstantiationFailed", descr.getId(), ie); //$NON-NLS-1$
} catch (IllegalAccessException iae) {
throw new PluginLifecycleException(
StandardObjectFactory.PACKAGE_NAME,
"pluginClassInstantiationFailed", descr.getId(), iae); //$NON-NLS-1$
}
}
/**
* This method does nothing in this implementation.
* @see org.java.plugin.standard.PluginLifecycleHandler#beforePluginStart(
* org.java.plugin.Plugin)
*/
@Override
protected void beforePluginStart(final Plugin plugin) {
// no-op
}
/**
* This method does nothing in this implementation.
* @see org.java.plugin.standard.PluginLifecycleHandler#afterPluginStop(
* org.java.plugin.Plugin)
*/
@Override
protected void afterPluginStop(final Plugin plugin) {
// no-op
}
/**
* This method does nothing in this implementation.
* @see org.java.plugin.standard.PluginLifecycleHandler#dispose()
*/
@Override
protected void dispose() {
// no-op
}
/**
* @see org.java.plugin.standard.PluginLifecycleHandler#configure(
* ExtendedProperties)
*/
@Override
public void configure(ExtendedProperties config) {
probeParentLoaderLast = "true".equalsIgnoreCase( //$NON-NLS-1$
config.getProperty("probeParentLoaderLast", "false")); //$NON-NLS-1$ //$NON-NLS-2$
log.debug("probeParentLoaderLast parameter value is " //$NON-NLS-1$
+ probeParentLoaderLast);
stickySynchronizing = "true".equalsIgnoreCase( //$NON-NLS-1$
config.getProperty("stickySynchronizing", "false")); //$NON-NLS-1$ //$NON-NLS-2$
log.debug("stickySynchronizing parameter value is " //$NON-NLS-1$
+ stickySynchronizing);
localClassLoadingOptimization = !"false".equalsIgnoreCase( //$NON-NLS-1$
config.getProperty("localClassLoadingOptimization", //$NON-NLS-1$
"true")); //$NON-NLS-1$
log.debug("localLoadingClassOptimization parameter value is " //$NON-NLS-1$
+ localClassLoadingOptimization);
foreignClassLoadingOptimization = !"false".equalsIgnoreCase( //$NON-NLS-1$
config.getProperty("foreignClassLoadingOptimization", //$NON-NLS-1$
"true")); //$NON-NLS-1$
log.debug("foreignClassLoadingOptimization parameter value is " //$NON-NLS-1$
+ foreignClassLoadingOptimization);
}
}
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