org.apache.openjpa.util.ClassResolverImpl Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
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* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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
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* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.openjpa.util;
import java.security.AccessController;
import org.apache.openjpa.lib.util.J2DoPrivHelper;
import org.apache.openjpa.lib.util.MultiClassLoader;
/**
* Default class resolver implementation.
*
* @since 0.3.0
* @author Abe White
*/
public class ClassResolverImpl
implements ClassResolver {
@Override
public ClassLoader getClassLoader(Class contextClass, ClassLoader envLoader) {
// get the context class' loader; if the class was loaded by the
// bootstrap loader, use the system classloader in the hopes that
// class.forName calls on it will find the bootstrap loader's cached
// class (the bootstrap loader is the parent of the system loader)
ClassLoader contextLoader = null;
if (contextClass != null) {
contextLoader = AccessController.doPrivileged(
J2DoPrivHelper.getClassLoaderAction(contextClass));
if (contextLoader == null)
contextLoader = AccessController.doPrivileged(
J2DoPrivHelper.getSystemClassLoaderAction());
}
// if there is only one unique loader, just return it
ClassLoader threadLoader = AccessController.doPrivileged(
J2DoPrivHelper.getContextClassLoaderAction());
if ((contextLoader == null || contextLoader == threadLoader)
&& (envLoader == null || envLoader == threadLoader))
return threadLoader;
// construct a multi class loader that will delegate in the order
// described in section 12.5 of the spec
MultiClassLoader loader = AccessController
.doPrivileged(J2DoPrivHelper.newMultiClassLoaderAction());
if (contextLoader != null)
loader.addClassLoader(contextLoader);
loader.addClassLoader(threadLoader);
if (envLoader != null)
loader.addClassLoader(envLoader);
return loader;
}
}