/*************************GO-LICENSE-START*********************************
* Copyright 2014 ThoughtWorks, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*************************GO-LICENSE-END***********************************/
package com.thoughtworks.go.agent.common.util;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* This classloader allows loading of classes from parent classloader ONLY for classes mentioned in permitted-classes list
* if given empty list of classes, it will allow loading of any class
*/
public final class ParentClassAccessFilteringClassloader extends ClassLoader {
private static final Log LOG = LogFactory.getLog(ParentClassAccessFilteringClassloader.class);
private final Class[] permittedParentDefns;
public ParentClassAccessFilteringClassloader(ClassLoader parent, Class... permittedParentDefns) {
super(parent);
this.permittedParentDefns = permittedParentDefns;
}
@Override protected Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException {
if (permittedParentDefns.length == 0) {
return super.loadClass(name, false);
}
for (Class permittedParentDefn : permittedParentDefns) {
if (permittedParentDefn.getCanonicalName().equals(name)) {
ClassLoader parent = getParent();
LOG.info(String.format("Loading %s using %s", name, parent == null ? "null classloader" : parent.getClass().getCanonicalName()));
return super.loadClass(name, false);
}
}
return getSystemClassLoader().loadClass(name);
}
}