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Micro Distribution of the Payara Project
/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* Copyright [2016-2019] [Payara Foundation and/or its affiliates]
*
* The contents of this file are subject to the terms of either the GNU
* General Public License Version 2 only ("GPL") or the Common Development
* and Distribution License("CDDL") (collectively, the "License"). You
* may not use this file except in compliance with the License. You can
* obtain a copy of the License at
* https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
* or packager/legal/LICENSE.txt. See the License for the specific
* language governing permissions and limitations under the License.
*
* When distributing the software, include this License Header Notice in each
* file and include the License file at packager/legal/LICENSE.txt.
*
* GPL Classpath Exception:
* Oracle designates this particular file as subject to the "Classpath"
* exception as provided by Oracle in the GPL Version 2 section of the License
* file that accompanied this code.
*
* Modifications:
* If applicable, add the following below the License Header, with the fields
* enclosed by brackets [] replaced by your own identifying information:
* "Portions Copyright [year] [name of copyright owner]"
*
* Contributor(s):
* If you wish your version of this file to be governed by only the CDDL or
* only the GPL Version 2, indicate your decision by adding "[Contributor]
* elects to include this software in this distribution under the [CDDL or GPL
* Version 2] license." If you don't indicate a single choice of license, a
* recipient has the option to distribute your version of this file under
* either the CDDL, the GPL Version 2 or to extend the choice of license to
* its licensees as provided above. However, if you add GPL Version 2 code
* and therefore, elected the GPL Version 2 license, then the option applies
* only if the new code is made subject to such option by the copyright
* holder.
*/
package com.sun.enterprise.loader;
import com.sun.enterprise.util.CULoggerInfo;
import java.net.URL;
import java.net.URLClassLoader;
import java.net.URLStreamHandlerFactory;
import java.util.logging.Logger;
/**
* As the name suggests, loads classes via current class loader ahead of parent class loader
* by default, classes are loaded from the parent ClassLoader first, thus this class is
* needed to allow overriding App Server's Modules / JAR files by placing them
* into <domain_dir>/lib or EAR lib directory
* @author lprimak
*/
public class CurrentBeforeParentClassLoader extends URLClassLoader {
public CurrentBeforeParentClassLoader(URL[] urls, ClassLoader parent) {
super(urls, parent);
}
public CurrentBeforeParentClassLoader(URL[] urls) {
super(urls);
}
public CurrentBeforeParentClassLoader(URL[] urls, ClassLoader parent, URLStreamHandlerFactory factory) {
super(urls, parent, factory);
}
/**
* Local-first class loading, instead of parent-first as the ClassLoader.loadClass() does
*
* @param name
* @param resolve
* @return Loaded class
* @throws ClassNotFoundException
*/
@Override
protected Class loadClass(String name, boolean resolve) throws ClassNotFoundException {
boolean isWhitelisted = isWhitelistEnabled() && isWhiteListed(name);
if((!currentBeforeParentEnabled && (isWhitelistEnabled()? isWhitelisted : true)) || isAlwaysDelegate(name))
{
return super.loadClass(name, resolve);
}
synchronized (getClassLoadingLock(name)) {
// First, check if the class has already been loaded
Class c = findLoadedClass(name);
if(c != null) {
return c;
}
try {
c = findClass(name);
logger.finest(String.format("Found Locally: %s - %s", name, c.getName()));
}
catch(ClassNotFoundException e) {
if(!isWhitelistEnabled() || isWhitelisted) {
logger.finest(String.format("Not Found Locally - Looking in Parent: %s", name));
return parent.loadClass(name);
}
else {
throw new ClassNotFoundException(String.format("Whitelist enabled, but class [%s] is not whitelisted", name), e);
}
}
if (resolve) {
resolveClass(c);
}
return c;
}
}
/**
* support for extreme class loading
*
* @param className
* @return true if white-listed
*/
protected boolean isWhiteListed(String className) {
return false;
}
/**
* @return true if extreme classloading is enabled
*/
protected boolean isWhitelistEnabled() {
return false;
}
/**
* enable current-first behavior
* conditional upon PARENT_CLASSLOADER_DELEGATE_PROPERTY system property being turned on
*/
public final void enableCurrentBeforeParent() {
String parentClassLoaderDelegateStr = System.getProperty(PARENT_CLASSLOADER_DELEGATE_PROPERTY, "true");
if(!Boolean.parseBoolean(parentClassLoaderDelegateStr)) {
currentBeforeParentEnabled = true;
}
}
/**
* enable current-first behavior unconditionally, regardless of system property
* used by application configuration parser, so if application developer uses the config xml element,
* they presumably want the behavior regardless of the system property settings
*/
public final void enableCurrentBeforeParentUnconditional() {
currentBeforeParentEnabled = true;
}
/**
* disable functionality
*/
public final void disableCurrentBeforeParent() {
currentBeforeParentEnabled = false;
}
private boolean isAlwaysDelegate(String name) {
return name.startsWith("sun") || name.startsWith("javax") || name.startsWith("jakarta");
}
@Override
public void addURL(URL url){
super.addURL(url);
}
protected boolean currentBeforeParentEnabled = false;
private final ClassLoader system = getClass().getClassLoader();
private final ClassLoader _parent = getParent();
private final ClassLoader parent = _parent != null? _parent : system;
private static final Logger logger = CULoggerInfo.getLogger();
public static final String PARENT_CLASSLOADER_DELEGATE_PROPERTY = "fish.payara.classloading.delegate";
}