org.jvnet.hk2.internal.DelegatingClassLoader Maven / Gradle / Ivy
/*
* Copyright (c) 2012, 2018 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0, which is available at
* http://www.eclipse.org/legal/epl-2.0.
*
* This Source Code may also be made available under the following Secondary
* Licenses when the conditions for such availability set forth in the
* Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
* version 2 with the GNU Classpath Exception, which is available at
* https://www.gnu.org/software/classpath/license.html.
*
* SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
*/
package org.jvnet.hk2.internal;
import java.net.URL;
import org.glassfish.hk2.utilities.reflection.Pretty;
/**
* A classloader that delegates first to an optional parent and then to a delegate loader
*/
class DelegatingClassLoader extends ClassLoader {
private final ClassLoader delegates[];
/**
* Constructor for special classloader to give to proxy making code
*
* @param parent the java-style classloader parent of this loader
* @param classLoaderDelegates other classloaders to delegate to
*/
DelegatingClassLoader(ClassLoader parent, ClassLoader... classLoaderDelegates) {
super(parent);
delegates=classLoaderDelegates;
}
@Override
public Class> loadClass(String clazz)
throws ClassNotFoundException {
if (getParent() != null) {
try {
return getParent().loadClass(clazz);
} catch (ClassNotFoundException cnfe) {}
}
ClassNotFoundException firstFail = null;
for (ClassLoader delegate : delegates) {
try {
return delegate.loadClass(clazz);
}
catch (ClassNotFoundException ncfe) {
if (firstFail == null) firstFail = ncfe;
}
}
if (firstFail != null) throw firstFail;
throw new ClassNotFoundException("Could not find " + clazz);
}
@Override
public URL getResource(String resource) {
if (getParent() != null) {
URL u = getParent().getResource(resource);
if (u != null) {
return u;
}
}
for (ClassLoader delegate : delegates) {
URL u = delegate.getResource(resource);
if (u != null) return u;
}
return null;
}
@Override
public String toString() {
return "DelegatingClassLoader(" + getParent() + "," +
Pretty.array(delegates) + "," + System.identityHashCode(this) + ")";
}
}
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