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	/*
	* Copyright (c) 1999, 2011, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package com.sun.naming.internal;

	import java.io.InputStream;
	import java.io.IOException;
	import java.net.MalformedURLException;
	import java.net.URLClassLoader;
	import java.net.URL;
	import java.security.AccessController;
	import java.security.PrivilegedAction;
	import java.security.PrivilegedActionException;
	import java.security.PrivilegedExceptionAction;
	import java.util.Enumeration;
	import java.util.NoSuchElementException;
	import java.util.Properties;

	import javax.naming.*;

	/**
	* VersionHelper was used by JNDI to accommodate differences between
	* JDK 1.1.x and the Java 2 platform. As this is no longer necessary
	* since JNDI's inclusion in the platform, this class currently
	* serves as a set of utilities for performing system-level things,
	* such as class-loading and reading system properties.
	*
	* @author Rosanna Lee
	* @author Scott Seligman
	*/

	final class VersionHelper12 extends VersionHelper {

	// Disallow external from creating one of these.
	VersionHelper12() {
	}

	public Class<?> loadClass(String className) throws ClassNotFoundException {
	return loadClass(className, getContextClassLoader());
	}

	public Class<?> loadClassWithoutInit(String className) throws ClassNotFoundException {
	return loadClass(className, false, getContextClassLoader());
	}

	/**
	* Determines whether classes may be loaded from an arbitrary URL code base.
	*/
	private static final String TRUST_URL_CODEBASE_PROPERTY =
	"com.sun.jndi.ldap.object.trustURLCodebase";
	private static final String trustURLCodebase =
	AccessController.doPrivileged(
	new PrivilegedAction<String>() {
	public String run() {
	try {
	return System.getProperty(TRUST_URL_CODEBASE_PROPERTY,
	"false");
	} catch (SecurityException e) {
	return "false";
	}
	}
	}
	);

	/**
	* Package private.
	*
	* This internal method is used with Thread Context Class Loader (TCCL),
	* please don't expose this method as public.
	*/
	Class<?> loadClass(String className, boolean initialize, ClassLoader cl)
	throws ClassNotFoundException {
	Class<?> cls = Class.forName(className, initialize, cl);
	return cls;
	}

	Class<?> loadClass(String className, ClassLoader cl)
	throws ClassNotFoundException {
	return loadClass(className, true, cl);
	}

	/**
	* @param className A non-null fully qualified class name.
	* @param codebase A non-null, space-separated list of URL strings.
	*/
	public Class<?> loadClass(String className, String codebase)
	throws ClassNotFoundException, MalformedURLException {
	if ("true".equalsIgnoreCase(trustURLCodebase)) {
	ClassLoader parent = getContextClassLoader();
	ClassLoader cl =
	URLClassLoader.newInstance(getUrlArray(codebase), parent);

	return loadClass(className, cl);
	} else {
	return null;
	}
	}

	String getJndiProperty(final int i) {
	return AccessController.doPrivileged(
	new PrivilegedAction<String>() {
	public String run() {
	try {
	return System.getProperty(PROPS[i]);
	} catch (SecurityException e) {
	return null;
	}
	}
	}
	);
	}

	String[] getJndiProperties() {
	Properties sysProps = AccessController.doPrivileged(
	new PrivilegedAction<Properties>() {
	public Properties run() {
	try {
	return System.getProperties();
	} catch (SecurityException e) {
	return null;
	}
	}
	}
	);
	if (sysProps == null) {
	return null;
	}
	String[] jProps = new String[PROPS.length];
	for (int i = 0; i < PROPS.length; i++) {
	jProps[i] = sysProps.getProperty(PROPS[i]);
	}
	return jProps;
	}

	InputStream getResourceAsStream(final Class<?> c, final String name) {
	return AccessController.doPrivileged(
	new PrivilegedAction<InputStream>() {
	public InputStream run() {
	return c.getResourceAsStream(name);
	}
	}
	);
	}

	InputStream getJavaHomeLibStream(final String filename) {
	return AccessController.doPrivileged(
	new PrivilegedAction<InputStream>() {
	public InputStream run() {
	try {
	String javahome = System.getProperty("java.home");
	if (javahome == null) {
	return null;
	}
	String pathname = javahome + java.io.File.separator +
	"lib" + java.io.File.separator + filename;
	return new java.io.FileInputStream(pathname);
	} catch (Exception e) {
	return null;
	}
	}
	}
	);
	}

	NamingEnumeration<InputStream> getResources(final ClassLoader cl,
	final String name) throws IOException {
	Enumeration<URL> urls;
	try {
	urls = AccessController.doPrivileged(
	new PrivilegedExceptionAction<Enumeration<URL>>() {
	public Enumeration<URL> run() throws IOException {
	return (cl == null)
	? ClassLoader.getSystemResources(name)
	: cl.getResources(name);
	}
	}
	);
	} catch (PrivilegedActionException e) {
	throw (IOException)e.getException();
	}
	return new InputStreamEnumeration(urls);
	}

	/**
	* Package private.
	*
	* This internal method returns Thread Context Class Loader (TCCL),
	* if null, returns the system Class Loader.
	*
	* Please don't expose this method as public.
	*/
	ClassLoader getContextClassLoader() {

	return AccessController.doPrivileged(
	new PrivilegedAction<ClassLoader>() {
	public ClassLoader run() {
	ClassLoader loader =
	Thread.currentThread().getContextClassLoader();
	if (loader == null) {
	// Don't use bootstrap class loader directly!
	loader = ClassLoader.getSystemClassLoader();
	}

	return loader;
	}
	}
	);
	}

	/**
	* Given an enumeration of URLs, an instance of this class represents
	* an enumeration of their InputStreams. Each operation on the URL
	* enumeration is performed within a doPrivileged block.
	* This is used to enumerate the resources under a foreign codebase.
	* This class is not MT-safe.
	*/
	class InputStreamEnumeration implements NamingEnumeration<InputStream> {

	private final Enumeration<URL> urls;

	private InputStream nextElement = null;

	InputStreamEnumeration(Enumeration<URL> urls) {
	this.urls = urls;
	}

	/*
	* Returns the next InputStream, or null if there are no more.
	* An InputStream that cannot be opened is skipped.
	*/
	private InputStream getNextElement() {
	return AccessController.doPrivileged(
	new PrivilegedAction<InputStream>() {
	public InputStream run() {
	while (urls.hasMoreElements()) {
	try {
	return urls.nextElement().openStream();
	} catch (IOException e) {
	// skip this URL
	}
	}
	return null;
	}
	}
	);
	}

	public boolean hasMore() {
	if (nextElement != null) {
	return true;
	}
	nextElement = getNextElement();
	return (nextElement != null);
	}

	public boolean hasMoreElements() {
	return hasMore();
	}

	public InputStream next() {
	if (hasMore()) {
	InputStream res = nextElement;
	nextElement = null;
	return res;
	} else {
	throw new NoSuchElementException();
	}
	}

	public InputStream nextElement() {
	return next();
	}

	public void close() {
	}
	}
	}

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