jaxp/src/javax/xml/parsers/FactoryFinder.java - platform/libcore - Git at Google

 /*
  * Copyright (c) 2003, 2006, 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 javax.xml.parsers;

 import java.io.BufferedReader;
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.util.Properties;

 /**
  * <p>Implements pluggable Datatypes.</p>
  *
  * <p>This class is duplicated for each JAXP subpackage so keep it in
  * sync.  It is package private for secure class loading.</p>
  *
  * @author Santiago.PericasGeertsen@sun.com
  * @author Huizhe.Wang@oracle.com
  */
 class FactoryFinder {

     /**
      * Internal debug flag.
      */
     private static boolean debug = false;

     /**
      * Cache for properties in java.home/lib/jaxp.properties
      */
     static Properties cacheProps = new Properties();

     /**
      * Flag indicating if properties from java.home/lib/jaxp.properties
      * have been cached.
      */
     static volatile boolean firstTime = true;

     /**
      * Security support class use to check access control before
      * getting certain system resources.
      */
     static SecuritySupport ss = new SecuritySupport();

     // Define system property "jaxp.debug" to get output
     static {
         // Use try/catch block to support applets, which throws
         // SecurityException out of this code.
         try {
             String val = ss.getSystemProperty("jaxp.debug");
             // Allow simply setting the prop to turn on debug
             debug = val != null && !"false".equals(val);
         }
         catch (SecurityException se) {
             debug = false;
         }
     }

     private static void dPrint(String msg) {
         if (debug) {
             System.err.println("JAXP: " + msg);
         }
     }

     /**
      * Attempt to load a class using the class loader supplied. If that fails
      * and fall back is enabled, the current (i.e. bootstrap) class loader is
      * tried.
      *
      * If the class loader supplied is <code>null</code>, first try using the
      * context class loader followed by the current (i.e. bootstrap) class
      * loader.
      *
      * Use bootstrap classLoader if cl = null and useBSClsLoader is true
      */
     static private Class getProviderClass(String className, ClassLoader cl,
             boolean doFallback, boolean useBSClsLoader) throws ClassNotFoundException
     {
         try {
             if (cl == null) {
                 if (useBSClsLoader) {
                     return Class.forName(className, true, FactoryFinder.class.getClassLoader());
                 } else {
                     cl = ss.getContextClassLoader();
                     if (cl == null) {
                         throw new ClassNotFoundException();
                     }
                     else {
                         return cl.loadClass(className);
                     }
                 }
             }
             else {
                 return cl.loadClass(className);
             }
         }
         catch (ClassNotFoundException e1) {
             if (doFallback) {
                 // Use current class loader - should always be bootstrap CL
                 return Class.forName(className, true, FactoryFinder.class.getClassLoader());
             }
             else {
                 throw e1;
             }
         }
     }

     /**
      * Create an instance of a class. Delegates to method
      * <code>getProviderClass()</code> in order to load the class.
      *
      * @param className Name of the concrete class corresponding to the
      * service provider
      *
      * @param cl <code>ClassLoader</code> used to load the factory class. If <code>null</code>
      * current <code>Thread</code>'s context classLoader is used to load the factory class.
      *
      * @param doFallback True if the current ClassLoader should be tried as
      * a fallback if the class is not found using cl
      */
     static Object newInstance(String className, ClassLoader cl, boolean doFallback)
         throws ConfigurationError
     {
         return newInstance(className, cl, doFallback, false);
     }

     /**
      * Create an instance of a class. Delegates to method
      * <code>getProviderClass()</code> in order to load the class.
      *
      * @param className Name of the concrete class corresponding to the
      * service provider
      *
      * @param cl <code>ClassLoader</code> used to load the factory class. If <code>null</code>
      * current <code>Thread</code>'s context classLoader is used to load the factory class.
      *
      * @param doFallback True if the current ClassLoader should be tried as
      * a fallback if the class is not found using cl
      *
      * @param useBSClsLoader True if cl=null actually meant bootstrap classLoader. This parameter
      * is needed since DocumentBuilderFactory/SAXParserFactory defined null as context classLoader.
      */
     static Object newInstance(String className, ClassLoader cl, boolean doFallback, boolean useBSClsLoader)
         throws ConfigurationError
     {
         try {
             Class providerClass = getProviderClass(className, cl, doFallback, useBSClsLoader);
             Object instance = providerClass.newInstance();
             if (debug) {    // Extra check to avoid computing cl strings
                 dPrint("created new instance of " + providerClass +
                        " using ClassLoader: " + cl);
             }
             return instance;
         }
         catch (ClassNotFoundException x) {
             throw new ConfigurationError(
                 "Provider " + className + " not found", x);
         }
         catch (Exception x) {
             throw new ConfigurationError(
                 "Provider " + className + " could not be instantiated: " + x,
                 x);
         }
     }

     /**
      * Finds the implementation Class object in the specified order.  Main
      * entry point.
      * @return Class object of factory, never null
      *
      * @param factoryId             Name of the factory to find, same as
      *                              a property name
      * @param fallbackClassName     Implementation class name, if nothing else
      *                              is found.  Use null to mean no fallback.
      *
      * Package private so this code can be shared.
      */
     static Object find(String factoryId, String fallbackClassName)
         throws ConfigurationError
     {
         dPrint("find factoryId =" + factoryId);

         // Use the system property first
         try {
             String systemProp = ss.getSystemProperty(factoryId);
             if (systemProp != null) {
                 dPrint("found system property, value=" + systemProp);
                 return newInstance(systemProp, null, true);
             }
         }
         catch (SecurityException se) {
             if (debug) se.printStackTrace();
         }

         // try to read from $java.home/lib/jaxp.properties
         try {
             String factoryClassName = null;
             if (firstTime) {
                 synchronized (cacheProps) {
                     if (firstTime) {
                         String configFile = ss.getSystemProperty("java.home") + File.separator +
                             "lib" + File.separator + "jaxp.properties";
                         File f = new File(configFile);
                         firstTime = false;
                         if (ss.doesFileExist(f)) {
                             dPrint("Read properties file "+f);
                             cacheProps.load(ss.getFileInputStream(f));
                         }
                     }
                 }
             }
             factoryClassName = cacheProps.getProperty(factoryId);

             if (factoryClassName != null) {
                 dPrint("found in $java.home/jaxp.properties, value=" + factoryClassName);
                 return newInstance(factoryClassName, null, true);
             }
         }
         catch (Exception ex) {
             if (debug) ex.printStackTrace();
         }

         // Try Jar Service Provider Mechanism
         Object provider = findJarServiceProvider(factoryId);
         if (provider != null) {
             return provider;
         }
         if (fallbackClassName == null) {
             throw new ConfigurationError(
                 "Provider for " + factoryId + " cannot be found", null);
         }

         dPrint("loaded from fallback value: " + fallbackClassName);
         return newInstance(fallbackClassName, null, true);
     }

     /*
      * Try to find provider using Jar Service Provider Mechanism
      *
      * @return instance of provider class if found or null
      */
     private static Object findJarServiceProvider(String factoryId)
         throws ConfigurationError
     {
         String serviceId = "META-INF/services/" + factoryId;
         InputStream is = null;

         // First try the Context ClassLoader
         ClassLoader cl = ss.getContextClassLoader();
         boolean useBSClsLoader = false;
         if (cl != null) {
             is = ss.getResourceAsStream(cl, serviceId);

             // If no provider found then try the current ClassLoader
             if (is == null) {
                 cl = FactoryFinder.class.getClassLoader();
                 is = ss.getResourceAsStream(cl, serviceId);
                 useBSClsLoader = true;
             }
         } else {
             // No Context ClassLoader, try the current ClassLoader
             cl = FactoryFinder.class.getClassLoader();
             is = ss.getResourceAsStream(cl, serviceId);
             useBSClsLoader = true;
         }

         if (is == null) {
             // No provider found
             return null;
         }

         if (debug) {    // Extra check to avoid computing cl strings
             dPrint("found jar resource=" + serviceId + " using ClassLoader: " + cl);
         }

         BufferedReader rd;
         try {
             rd = new BufferedReader(new InputStreamReader(is, "UTF-8"));
         }
         catch (java.io.UnsupportedEncodingException e) {
             rd = new BufferedReader(new InputStreamReader(is));
         }

         String factoryClassName = null;
         try {
             // XXX Does not handle all possible input as specified by the
             // Jar Service Provider specification
             factoryClassName = rd.readLine();
             rd.close();
         } catch (IOException x) {
             // No provider found
             return null;
         }

         if (factoryClassName != null && !"".equals(factoryClassName)) {
             dPrint("found in resource, value=" + factoryClassName);

             // Note: here we do not want to fall back to the current
             // ClassLoader because we want to avoid the case where the
             // resource file was found using one ClassLoader and the
             // provider class was instantiated using a different one.
             return newInstance(factoryClassName, cl, false, useBSClsLoader);
         }

         // No provider found
         return null;
     }

     static class ConfigurationError extends Error {
         private Exception exception;

         /**
          * Construct a new instance with the specified detail string and
          * exception.
          */
         ConfigurationError(String msg, Exception x) {
             super(msg);
             this.exception = x;
         }

         Exception getException() {
             return exception;
         }
         /**
         * use the exception chaining mechanism of JDK1.4
         */
         @Override
         public Throwable getCause() {
             return exception;
         }
     }

 }
	/*
	* Copyright (c) 2003, 2006, 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 javax.xml.parsers;

	import java.io.BufferedReader;
	import java.io.File;
	import java.io.IOException;
	import java.io.InputStream;
	import java.io.InputStreamReader;
	import java.util.Properties;

	/**
	* <p>Implements pluggable Datatypes.</p>
	*
	* <p>This class is duplicated for each JAXP subpackage so keep it in
	* sync. It is package private for secure class loading.</p>
	*
	* @author Santiago.PericasGeertsen@sun.com
	* @author Huizhe.Wang@oracle.com
	*/
	class FactoryFinder {

	/**
	* Internal debug flag.
	*/
	private static boolean debug = false;

	/**
	* Cache for properties in java.home/lib/jaxp.properties
	*/
	static Properties cacheProps = new Properties();

	/**
	* Flag indicating if properties from java.home/lib/jaxp.properties
	* have been cached.
	*/
	static volatile boolean firstTime = true;

	/**
	* Security support class use to check access control before
	* getting certain system resources.
	*/
	static SecuritySupport ss = new SecuritySupport();

	// Define system property "jaxp.debug" to get output
	static {
	// Use try/catch block to support applets, which throws
	// SecurityException out of this code.
	try {
	String val = ss.getSystemProperty("jaxp.debug");
	// Allow simply setting the prop to turn on debug
	debug = val != null && !"false".equals(val);
	}
	catch (SecurityException se) {
	debug = false;
	}
	}

	private static void dPrint(String msg) {
	if (debug) {
	System.err.println("JAXP: " + msg);
	}
	}

	/**
	* Attempt to load a class using the class loader supplied. If that fails
	* and fall back is enabled, the current (i.e. bootstrap) class loader is
	* tried.
	*
	* If the class loader supplied is <code>null</code>, first try using the
	* context class loader followed by the current (i.e. bootstrap) class
	* loader.
	*
	* Use bootstrap classLoader if cl = null and useBSClsLoader is true
	*/
	static private Class getProviderClass(String className, ClassLoader cl,
	boolean doFallback, boolean useBSClsLoader) throws ClassNotFoundException
	{
	try {
	if (cl == null) {
	if (useBSClsLoader) {
	return Class.forName(className, true, FactoryFinder.class.getClassLoader());
	} else {
	cl = ss.getContextClassLoader();
	if (cl == null) {
	throw new ClassNotFoundException();
	}
	else {
	return cl.loadClass(className);
	}
	}
	}
	else {
	return cl.loadClass(className);
	}
	}
	catch (ClassNotFoundException e1) {
	if (doFallback) {
	// Use current class loader - should always be bootstrap CL
	return Class.forName(className, true, FactoryFinder.class.getClassLoader());
	}
	else {
	throw e1;
	}
	}
	}

	/**
	* Create an instance of a class. Delegates to method
	* <code>getProviderClass()</code> in order to load the class.
	*
	* @param className Name of the concrete class corresponding to the
	* service provider
	*
	* @param cl <code>ClassLoader</code> used to load the factory class. If <code>null</code>
	* current <code>Thread</code>'s context classLoader is used to load the factory class.
	*
	* @param doFallback True if the current ClassLoader should be tried as
	* a fallback if the class is not found using cl
	*/
	static Object newInstance(String className, ClassLoader cl, boolean doFallback)
	throws ConfigurationError
	{
	return newInstance(className, cl, doFallback, false);
	}

	/**
	* Create an instance of a class. Delegates to method
	* <code>getProviderClass()</code> in order to load the class.
	*
	* @param className Name of the concrete class corresponding to the
	* service provider
	*
	* @param cl <code>ClassLoader</code> used to load the factory class. If <code>null</code>
	* current <code>Thread</code>'s context classLoader is used to load the factory class.
	*
	* @param doFallback True if the current ClassLoader should be tried as
	* a fallback if the class is not found using cl
	*
	* @param useBSClsLoader True if cl=null actually meant bootstrap classLoader. This parameter
	* is needed since DocumentBuilderFactory/SAXParserFactory defined null as context classLoader.
	*/
	static Object newInstance(String className, ClassLoader cl, boolean doFallback, boolean useBSClsLoader)
	throws ConfigurationError
	{
	try {
	Class providerClass = getProviderClass(className, cl, doFallback, useBSClsLoader);
	Object instance = providerClass.newInstance();
	if (debug) { // Extra check to avoid computing cl strings
	dPrint("created new instance of " + providerClass +
	" using ClassLoader: " + cl);
	}
	return instance;
	}
	catch (ClassNotFoundException x) {
	throw new ConfigurationError(
	"Provider " + className + " not found", x);
	}
	catch (Exception x) {
	throw new ConfigurationError(
	"Provider " + className + " could not be instantiated: " + x,
	x);
	}
	}

	/**
	* Finds the implementation Class object in the specified order. Main
	* entry point.
	* @return Class object of factory, never null
	*
	* @param factoryId Name of the factory to find, same as
	* a property name
	* @param fallbackClassName Implementation class name, if nothing else
	* is found. Use null to mean no fallback.
	*
	* Package private so this code can be shared.
	*/
	static Object find(String factoryId, String fallbackClassName)
	throws ConfigurationError
	{
	dPrint("find factoryId =" + factoryId);

	// Use the system property first
	try {
	String systemProp = ss.getSystemProperty(factoryId);
	if (systemProp != null) {
	dPrint("found system property, value=" + systemProp);
	return newInstance(systemProp, null, true);
	}
	}
	catch (SecurityException se) {
	if (debug) se.printStackTrace();
	}

	// try to read from $java.home/lib/jaxp.properties
	try {
	String factoryClassName = null;
	if (firstTime) {
	synchronized (cacheProps) {
	if (firstTime) {
	String configFile = ss.getSystemProperty("java.home") + File.separator +
	"lib" + File.separator + "jaxp.properties";
	File f = new File(configFile);
	firstTime = false;
	if (ss.doesFileExist(f)) {
	dPrint("Read properties file "+f);
	cacheProps.load(ss.getFileInputStream(f));
	}
	}
	}
	}
	factoryClassName = cacheProps.getProperty(factoryId);

	if (factoryClassName != null) {
	dPrint("found in $java.home/jaxp.properties, value=" + factoryClassName);
	return newInstance(factoryClassName, null, true);
	}
	}
	catch (Exception ex) {
	if (debug) ex.printStackTrace();
	}

	// Try Jar Service Provider Mechanism
	Object provider = findJarServiceProvider(factoryId);
	if (provider != null) {
	return provider;
	}
	if (fallbackClassName == null) {
	throw new ConfigurationError(
	"Provider for " + factoryId + " cannot be found", null);
	}

	dPrint("loaded from fallback value: " + fallbackClassName);
	return newInstance(fallbackClassName, null, true);
	}

	/*
	* Try to find provider using Jar Service Provider Mechanism
	*
	* @return instance of provider class if found or null
	*/
	private static Object findJarServiceProvider(String factoryId)
	throws ConfigurationError
	{
	String serviceId = "META-INF/services/" + factoryId;
	InputStream is = null;

	// First try the Context ClassLoader
	ClassLoader cl = ss.getContextClassLoader();
	boolean useBSClsLoader = false;
	if (cl != null) {
	is = ss.getResourceAsStream(cl, serviceId);

	// If no provider found then try the current ClassLoader
	if (is == null) {
	cl = FactoryFinder.class.getClassLoader();
	is = ss.getResourceAsStream(cl, serviceId);
	useBSClsLoader = true;
	}
	} else {
	// No Context ClassLoader, try the current ClassLoader
	cl = FactoryFinder.class.getClassLoader();
	is = ss.getResourceAsStream(cl, serviceId);
	useBSClsLoader = true;
	}

	if (is == null) {
	// No provider found
	return null;
	}

	if (debug) { // Extra check to avoid computing cl strings
	dPrint("found jar resource=" + serviceId + " using ClassLoader: " + cl);
	}

	BufferedReader rd;
	try {
	rd = new BufferedReader(new InputStreamReader(is, "UTF-8"));
	}
	catch (java.io.UnsupportedEncodingException e) {
	rd = new BufferedReader(new InputStreamReader(is));
	}

	String factoryClassName = null;
	try {
	// XXX Does not handle all possible input as specified by the
	// Jar Service Provider specification
	factoryClassName = rd.readLine();
	rd.close();
	} catch (IOException x) {
	// No provider found
	return null;
	}

	if (factoryClassName != null && !"".equals(factoryClassName)) {
	dPrint("found in resource, value=" + factoryClassName);

	// Note: here we do not want to fall back to the current
	// ClassLoader because we want to avoid the case where the
	// resource file was found using one ClassLoader and the
	// provider class was instantiated using a different one.
	return newInstance(factoryClassName, cl, false, useBSClsLoader);
	}

	// No provider found
	return null;
	}

	static class ConfigurationError extends Error {
	private Exception exception;

	/**
	* Construct a new instance with the specified detail string and
	* exception.
	*/
	ConfigurationError(String msg, Exception x) {
	super(msg);
	this.exception = x;
	}

	Exception getException() {
	return exception;
	}
	/**
	* use the exception chaining mechanism of JDK1.4
	*/
	@Override
	public Throwable getCause() {
	return exception;
	}
	}

	}