jdk/src/java.naming/share/classes/com/sun/naming/internal/VersionHelper.java - platform/libcore - Git at Google

 /*
  * Copyright (c) 1999, 2014, 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 javax.naming.NamingEnumeration;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.net.MalformedURLException;
 import java.net.URL;
 import java.net.URLClassLoader;
 import java.security.AccessController;
 import java.security.PrivilegedAction;
 import java.security.PrivilegedActionException;
 import java.security.PrivilegedExceptionAction;
 import java.util.*;

 /**
  * 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
  */

 public final class VersionHelper {
     private static final VersionHelper helper = new VersionHelper();

     final static String[] PROPS = new String[]{
         javax.naming.Context.INITIAL_CONTEXT_FACTORY,
         javax.naming.Context.OBJECT_FACTORIES,
         javax.naming.Context.URL_PKG_PREFIXES,
         javax.naming.Context.STATE_FACTORIES,
         javax.naming.Context.PROVIDER_URL,
         javax.naming.Context.DNS_URL,
         // The following shouldn't create a runtime dependence on ldap package.
         javax.naming.ldap.LdapContext.CONTROL_FACTORIES
     };

     public final static int INITIAL_CONTEXT_FACTORY = 0;
     public final static int OBJECT_FACTORIES = 1;
     public final static int URL_PKG_PREFIXES = 2;
     public final static int STATE_FACTORIES = 3;
     public final static int PROVIDER_URL = 4;
     public final static int DNS_URL = 5;
     public final static int CONTROL_FACTORIES = 6;

     private VersionHelper() {} // Disallow anyone from creating one of these.

     public static VersionHelper getVersionHelper() {
         return helper;
     }

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

     /**
      * @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 {

         ClassLoader parent = getContextClassLoader();
         ClassLoader cl =
                 URLClassLoader.newInstance(getUrlArray(codebase), parent);

         return loadClass(className, cl);
     }

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

     /*
      * Returns a JNDI property from the system properties. Returns
      * null if the property is not set, or if there is no permission
      * to read it.
      */
     String getJndiProperty(int i) {
         PrivilegedAction<String> act = () -> {
             try {
                 return System.getProperty(PROPS[i]);
             } catch (SecurityException e) {
                 return null;
             }
         };
         return AccessController.doPrivileged(act);
     }

     /*
      * Reads each property in PROPS from the system properties, and
      * returns their values -- in order -- in an array.  For each
      * unset property, the corresponding array element is set to null.
      * Returns null if there is no permission to call System.getProperties().
      */
     String[] getJndiProperties() {
         PrivilegedAction<Properties> act = () -> {
             try {
                 return System.getProperties();
             } catch (SecurityException e) {
                 return null;
             }
         };
         Properties sysProps = AccessController.doPrivileged(act);
         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;
     }

     private static String resolveName(Class<?> c, String name) {
         if (name == null) {
             return name;
         }
         if (!name.startsWith("/")) {
             while (c.isArray()) {
                 c = c.getComponentType();
             }
             String baseName = c.getName();
             int index = baseName.lastIndexOf('.');
             if (index != -1) {
                 name = baseName.substring(0, index).replace('.', '/')
                     +"/"+name;
             }
         } else {
             name = name.substring(1);
         }
         return name;
     }

     /*
      * Returns the resource of a given name associated with a particular
      * class (never null), or null if none can be found.
      */
     InputStream getResourceAsStream(Class<?> c, String name) {
         PrivilegedAction<InputStream> act = () -> {
             try {
                 java.lang.reflect.Module m = c.getModule();
                 return c.getModule().getResourceAsStream(resolveName(c,name));
              } catch (IOException x) {
                  return null;
              }
         };
         return AccessController.doPrivileged(act);
     }

     /*
      * Returns an input stream for a file in <java.home>/conf,
      * or null if it cannot be located or opened.
      *
      * @param filename  The file name, sans directory.
      */
     InputStream getJavaHomeConfStream(String filename) {
         PrivilegedAction<InputStream> act = () -> {
             try {
                 String javahome = System.getProperty("java.home");
                 if (javahome == null) {
                     return null;
                 }
                 String pathname = javahome + File.separator +
                         "conf" + File.separator + filename;
                 return new FileInputStream(pathname);
             } catch (Exception e) {
                 return null;
             }
         };
         return AccessController.doPrivileged(act);
     }

     /*
      * Returns an enumeration (never null) of InputStreams of the
      * resources of a given name associated with a particular class
      * loader.  Null represents the bootstrap class loader in some
      * Java implementations.
      */
     NamingEnumeration<InputStream> getResources(ClassLoader cl,
                                                 String name) throws IOException {
         Enumeration<URL> urls;
         PrivilegedExceptionAction<Enumeration<URL>> act = () ->
                 (cl == null)
                         ? ClassLoader.getSystemResources(name)
                         : cl.getResources(name);
         try {
             urls = AccessController.doPrivileged(act);
         } catch (PrivilegedActionException e) {
             throw (IOException) e.getException();
         }
         return new InputStreamEnumeration(urls);
     }


     /**
      * Package private.
      * <p>
      * This internal method returns Thread Context Class Loader (TCCL),
      * if null, returns the system Class Loader.
      * <p>
      * Please don't expose this method as public.
      * @throws SecurityException if the class loader is not accessible
      */
     ClassLoader getContextClassLoader() {

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

     private static URL[] getUrlArray(String codebase)
             throws MalformedURLException {
         // Parse codebase into separate URLs
         StringTokenizer parser = new StringTokenizer(codebase);
         List<String> list = new ArrayList<>();
         while (parser.hasMoreTokens()) {
             list.add(parser.nextToken());
         }
         String[] url = new String[list.size()];
         for (int i = 0; i < url.length; i++) {
             url[i] = list.get(i);
         }

         URL[] urlArray = new URL[url.length];
         for (int i = 0; i < urlArray.length; i++) {
             urlArray[i] = new URL(url[i]);
         }
         return urlArray;
     }

     /**
      * 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.
      */
     private class InputStreamEnumeration implements
             NamingEnumeration<InputStream> {

         private final Enumeration<URL> urls;

         private InputStream nextElement;

         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() {
             PrivilegedAction<InputStream> act = () -> {
                 while (urls.hasMoreElements()) {
                     try {
                         return urls.nextElement().openStream();
                     } catch (IOException e) {
                         // skip this URL
                     }
                 }
                 return null;
             };
             return AccessController.doPrivileged(act);
         }

         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() {
         }
     }
 }
	/*
	* Copyright (c) 1999, 2014, 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 javax.naming.NamingEnumeration;
	import java.io.File;
	import java.io.FileInputStream;
	import java.io.IOException;
	import java.io.InputStream;
	import java.net.MalformedURLException;
	import java.net.URL;
	import java.net.URLClassLoader;
	import java.security.AccessController;
	import java.security.PrivilegedAction;
	import java.security.PrivilegedActionException;
	import java.security.PrivilegedExceptionAction;
	import java.util.*;

	/**
	* 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
	*/

	public final class VersionHelper {
	private static final VersionHelper helper = new VersionHelper();

	final static String[] PROPS = new String[]{
	javax.naming.Context.INITIAL_CONTEXT_FACTORY,
	javax.naming.Context.OBJECT_FACTORIES,
	javax.naming.Context.URL_PKG_PREFIXES,
	javax.naming.Context.STATE_FACTORIES,
	javax.naming.Context.PROVIDER_URL,
	javax.naming.Context.DNS_URL,
	// The following shouldn't create a runtime dependence on ldap package.
	javax.naming.ldap.LdapContext.CONTROL_FACTORIES
	};

	public final static int INITIAL_CONTEXT_FACTORY = 0;
	public final static int OBJECT_FACTORIES = 1;
	public final static int URL_PKG_PREFIXES = 2;
	public final static int STATE_FACTORIES = 3;
	public final static int PROVIDER_URL = 4;
	public final static int DNS_URL = 5;
	public final static int CONTROL_FACTORIES = 6;

	private VersionHelper() {} // Disallow anyone from creating one of these.

	public static VersionHelper getVersionHelper() {
	return helper;
	}

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

	/**
	* @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 {

	ClassLoader parent = getContextClassLoader();
	ClassLoader cl =
	URLClassLoader.newInstance(getUrlArray(codebase), parent);

	return loadClass(className, cl);
	}

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

	/*
	* Returns a JNDI property from the system properties. Returns
	* null if the property is not set, or if there is no permission
	* to read it.
	*/
	String getJndiProperty(int i) {
	PrivilegedAction<String> act = () -> {
	try {
	return System.getProperty(PROPS[i]);
	} catch (SecurityException e) {
	return null;
	}
	};
	return AccessController.doPrivileged(act);
	}

	/*
	* Reads each property in PROPS from the system properties, and
	* returns their values -- in order -- in an array. For each
	* unset property, the corresponding array element is set to null.
	* Returns null if there is no permission to call System.getProperties().
	*/
	String[] getJndiProperties() {
	PrivilegedAction<Properties> act = () -> {
	try {
	return System.getProperties();
	} catch (SecurityException e) {
	return null;
	}
	};
	Properties sysProps = AccessController.doPrivileged(act);
	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;
	}

	private static String resolveName(Class<?> c, String name) {
	if (name == null) {
	return name;
	}
	if (!name.startsWith("/")) {
	while (c.isArray()) {
	c = c.getComponentType();
	}
	String baseName = c.getName();
	int index = baseName.lastIndexOf('.');
	if (index != -1) {
	name = baseName.substring(0, index).replace('.', '/')
	+"/"+name;
	}
	} else {
	name = name.substring(1);
	}
	return name;
	}

	/*
	* Returns the resource of a given name associated with a particular
	* class (never null), or null if none can be found.
	*/
	InputStream getResourceAsStream(Class<?> c, String name) {
	PrivilegedAction<InputStream> act = () -> {
	try {
	java.lang.reflect.Module m = c.getModule();
	return c.getModule().getResourceAsStream(resolveName(c,name));
	} catch (IOException x) {
	return null;
	}
	};
	return AccessController.doPrivileged(act);
	}

	/*
	* Returns an input stream for a file in <java.home>/conf,
	* or null if it cannot be located or opened.
	*
	* @param filename The file name, sans directory.
	*/
	InputStream getJavaHomeConfStream(String filename) {
	PrivilegedAction<InputStream> act = () -> {
	try {
	String javahome = System.getProperty("java.home");
	if (javahome == null) {
	return null;
	}
	String pathname = javahome + File.separator +
	"conf" + File.separator + filename;
	return new FileInputStream(pathname);
	} catch (Exception e) {
	return null;
	}
	};
	return AccessController.doPrivileged(act);
	}

	/*
	* Returns an enumeration (never null) of InputStreams of the
	* resources of a given name associated with a particular class
	* loader. Null represents the bootstrap class loader in some
	* Java implementations.
	*/
	NamingEnumeration<InputStream> getResources(ClassLoader cl,
	String name) throws IOException {
	Enumeration<URL> urls;
	PrivilegedExceptionAction<Enumeration<URL>> act = () ->
	(cl == null)
	? ClassLoader.getSystemResources(name)
	: cl.getResources(name);
	try {
	urls = AccessController.doPrivileged(act);
	} catch (PrivilegedActionException e) {
	throw (IOException) e.getException();
	}
	return new InputStreamEnumeration(urls);
	}


	/**
	* Package private.
	* <p>
	* This internal method returns Thread Context Class Loader (TCCL),
	* if null, returns the system Class Loader.
	* <p>
	* Please don't expose this method as public.
	* @throws SecurityException if the class loader is not accessible
	*/
	ClassLoader getContextClassLoader() {

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

	private static URL[] getUrlArray(String codebase)
	throws MalformedURLException {
	// Parse codebase into separate URLs
	StringTokenizer parser = new StringTokenizer(codebase);
	List<String> list = new ArrayList<>();
	while (parser.hasMoreTokens()) {
	list.add(parser.nextToken());
	}
	String[] url = new String[list.size()];
	for (int i = 0; i < url.length; i++) {
	url[i] = list.get(i);
	}

	URL[] urlArray = new URL[url.length];
	for (int i = 0; i < urlArray.length; i++) {
	urlArray[i] = new URL(url[i]);
	}
	return urlArray;
	}

	/**
	* 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.
	*/
	private class InputStreamEnumeration implements
	NamingEnumeration<InputStream> {

	private final Enumeration<URL> urls;

	private InputStream nextElement;

	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() {
	PrivilegedAction<InputStream> act = () -> {
	while (urls.hasMoreElements()) {
	try {
	return urls.nextElement().openStream();
	} catch (IOException e) {
	// skip this URL
	}
	}
	return null;
	};
	return AccessController.doPrivileged(act);
	}

	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() {
	}
	}
	}