org.apache.openjpa.util.GeneratedClasses Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* 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
* "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.
*/
package org.apache.openjpa.util;
import java.security.AccessController;
import org.apache.openjpa.lib.util.J2DoPrivHelper;
/**
* Utility methods when generating classes, including at runtime.
*
* @since 1.0.0
*/
public class GeneratedClasses {
/**
* Return the more derived loader of the class laoders for the given
* classes.
*/
public static ClassLoader getMostDerivedLoader(Class c1, Class c2) {
ClassLoader l1 = AccessController.doPrivileged(
J2DoPrivHelper.getClassLoaderAction(c1));
ClassLoader l2 = AccessController.doPrivileged(
J2DoPrivHelper.getClassLoaderAction(c2));
if (l1 == l2)
return l1;
if (l1 == null)
return l2;
if (l2 == null)
return l1;
if(canLoad(l1, c2)) {
return l1;
}
return l2;
}
public static Class loadAsmClass(String className, byte[] classBytes, Class proxiedClass, ClassLoader loader) {
ClassLoaderProxyService pcls = new ClassLoaderProxyService(null, loader);
try {
return pcls.defineAndLoad(className, classBytes, proxiedClass);
} catch (Throwable t) {
// this happens e.g when trying to create a proxy for a class with private access.
throw new GeneralException(className).setCause(t);
}
}
/**
* Return true if the given loader will load the same version of a given
* class.
*
* @param loader Classloader to use.
* @param clazz Expected class.
* @return true if loader.load(clazz.getName()) == clazz. Otherwise false.
*/
private static boolean canLoad(ClassLoader loader, Class clazz) {
Class loaded = null;
try {
loaded = loader.loadClass(clazz.getName());
} catch (ClassNotFoundException e) {
// Rely on caller to handle return value = false.
}
return clazz == loaded;
}
}