org.kitesdk.morphline.saxon.ClassLoaderUtil Maven / Gradle / Ivy
// Copied from nux-1.6
/*
* Copyright (c) 2005, The Regents of the University of California, through
* Lawrence Berkeley National Laboratory (subject to receipt of any required
* approvals from the U.S. Dept. of Energy). All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* (1) Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* (2) Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* (3) Neither the name of the University of California, Lawrence Berkeley
* National Laboratory, U.S. Dept. of Energy nor the names of its contributors
* may be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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package org.kitesdk.morphline.saxon;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Utility to instantiate objects via reflection in a safe way,
* even in weird multi class loader environments.
*
* This does basically the same as the SAX NewInstance class used by
* XMLReaderFactory.createXMLReader(String className).
*
* Also see javax.xml.parsers.FactoryFinder.newInstance(...)
*
* @author whoschek.AT.lbl.DOT.gov
* @author $Author: hoschek $
* @version $Revision: 1.1 $, $Date: 2006/12/07 04:56:46 $
*/
final class ClassLoaderUtil {
// if there is a weird ClassLoader related problem, try switching this flag
// and see if that helps
private static final boolean SIMPLE_MODE = false;
private static final boolean FALL_BACK = true;
private static final Logger LOG = LoggerFactory.getLogger(ClassLoaderUtil.class);
private ClassLoaderUtil() {} // not instantiable
public static Object newInstance(String className) throws ClassNotFoundException, InstantiationException, IllegalAccessException {
if (SIMPLE_MODE) return Class.forName(className).newInstance();
// instantiate a temporary dummy object and get its context class loader
ClassLoader classLoader = new ClassLoaderFinder().getContextClassLoader();
Class clazz;
if (classLoader == null) {
LOG.debug("No context class loader found");
clazz = Class.forName(className);
} else {
LOG.debug("Context class loader found");
try {
clazz = classLoader.loadClass(className);
} catch (ClassNotFoundException ex) {
if (FALL_BACK) {
// Fall back to current classloader (e.g. interactive eclipse invocation)
LOG.debug("Fall back to current classloader");
classLoader = ClassLoaderUtil.class.getClassLoader();
clazz = classLoader.loadClass(className);
} else {
throw ex;
}
}
}
return clazz.newInstance();
}
private static final class ClassLoaderFinder {
public ClassLoader getContextClassLoader() {
return Thread.currentThread().getContextClassLoader();
}
}
}