src/javax/xml/datatype/FactoryFinder.java - platform/external/jetbrains/jdk8u_jaxp - Git at Google

 /*
  * Copyright (c) 2004, 2013, 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.datatype;

 import java.io.File;
 import java.security.AccessController;
 import java.security.PrivilegedAction;
 import java.util.Iterator;
 import java.util.Properties;
 import java.util.ServiceConfigurationError;
 import java.util.ServiceLoader;

 /**
  * <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
  */
 class FactoryFinder {
     private static final String DEFAULT_PACKAGE = "com.sun.org.apache.xerces.internal";

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

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

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

     /**
      * Security support class use to check access control before
      * getting certain system resources.
      */
     private final 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, false, FactoryFinder.class.getClassLoader());
                 } else {
                     cl = ss.getContextClassLoader();
                     if (cl == null) {
                         throw new ClassNotFoundException();
                     }
                     else {
                         return Class.forName(className, false, cl);
                     }
                 }
             }
             else {
                 return Class.forName(className, false, cl);
             }
         }
         catch (ClassNotFoundException e1) {
             if (doFallback) {
                 // Use current class loader - should always be bootstrap CL
                 return Class.forName(className, false, 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 type Base class / Service interface  of the factory to
      *             instantiate.
      *
      * @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 <T> T newInstance(Class<T> type, String className, ClassLoader cl, boolean doFallback)
         throws  DatatypeConfigurationException
     {
         return newInstance(type, className, cl, doFallback, false);
     }

     /**
      * Create an instance of a class. Delegates to method
      * <code>getProviderClass()</code> in order to load the class.
      *
      * @param type Base class / Service interface  of the factory to
      *             instantiate.
      *
      * @param className Name of the concrete class corresponding to the
      * service provider
      *
      * @param cl ClassLoader to use to load the class, null means to use
      * the bootstrap ClassLoader
      *
      * @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 <T> T newInstance(Class<T> type, String className, ClassLoader cl,
             boolean doFallback, boolean useBSClsLoader)
         throws DatatypeConfigurationException
     {
         assert type != null;

         // make sure we have access to restricted packages
         if (System.getSecurityManager() != null) {
             if (className != null && className.startsWith(DEFAULT_PACKAGE)) {
                 cl = null;
                 useBSClsLoader = true;
             }
         }

         try {
             Class<?> providerClass = getProviderClass(className, cl, doFallback, useBSClsLoader);
             if (!type.isAssignableFrom(providerClass)) {
                 throw new ClassCastException(className + " cannot be cast to " + type.getName());
             }
             Object instance = providerClass.newInstance();
             if (debug) {    // Extra check to avoid computing cl strings
                 dPrint("created new instance of " + providerClass +
                        " using ClassLoader: " + cl);
             }
             return type.cast(instance);
         }
         catch (ClassNotFoundException x) {
             throw new DatatypeConfigurationException(
                 "Provider " + className + " not found", x);
         }
         catch (Exception x) {
             throw new DatatypeConfigurationException(
                 "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 type                  Base class / Service interface  of the
      *                              factory to find.
      * @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 <T> T find(Class<T> type, String fallbackClassName)
         throws DatatypeConfigurationException
     {
         final String factoryId = type.getName();
         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(type, systemProp, null, true);
             }
         }
         catch (SecurityException se) {
             if (debug) se.printStackTrace();
         }

         // try to read from $java.home/lib/jaxp.properties
         try {
             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));
                         }
                     }
                 }
             }
             final String factoryClassName = cacheProps.getProperty(factoryId);

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

         // Try Jar Service Provider Mechanism
         final T provider = findServiceProvider(type);
         if (provider != null) {
             return provider;
         }
         if (fallbackClassName == null) {
             throw new DatatypeConfigurationException(
                 "Provider for " + factoryId + " cannot be found");
         }

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

     /*
      * Try to find provider using the ServiceLoader API
      *
      * @param type Base class / Service interface  of the factory to find.
      *
      * @return instance of provider class if found or null
      */
     private static <T> T findServiceProvider(final Class<T> type)
             throws DatatypeConfigurationException
     {
         try {
             return AccessController.doPrivileged(new PrivilegedAction<T>() {
                 public T run() {
                     final ServiceLoader<T> serviceLoader = ServiceLoader.load(type);
                     final Iterator<T> iterator = serviceLoader.iterator();
                     if (iterator.hasNext()) {
                         return iterator.next();
                     } else {
                         return null;
                     }
                 }
             });
         } catch(ServiceConfigurationError e) {
             final DatatypeConfigurationException error =
                     new DatatypeConfigurationException(
                         "Provider for " + type + " cannot be found", e);
             throw error;
         }
     }

 }
	/*
	* Copyright (c) 2004, 2013, 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.datatype;

	import java.io.File;
	import java.security.AccessController;
	import java.security.PrivilegedAction;
	import java.util.Iterator;
	import java.util.Properties;
	import java.util.ServiceConfigurationError;
	import java.util.ServiceLoader;

	/**
	* <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
	*/
	class FactoryFinder {
	private static final String DEFAULT_PACKAGE = "com.sun.org.apache.xerces.internal";

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

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

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

	/**
	* Security support class use to check access control before
	* getting certain system resources.
	*/
	private final 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, false, FactoryFinder.class.getClassLoader());
	} else {
	cl = ss.getContextClassLoader();
	if (cl == null) {
	throw new ClassNotFoundException();
	}
	else {
	return Class.forName(className, false, cl);
	}
	}
	}
	else {
	return Class.forName(className, false, cl);
	}
	}
	catch (ClassNotFoundException e1) {
	if (doFallback) {
	// Use current class loader - should always be bootstrap CL
	return Class.forName(className, false, 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 type Base class / Service interface of the factory to
	* instantiate.
	*
	* @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 <T> T newInstance(Class<T> type, String className, ClassLoader cl, boolean doFallback)
	throws DatatypeConfigurationException
	{
	return newInstance(type, className, cl, doFallback, false);
	}

	/**
	* Create an instance of a class. Delegates to method
	* <code>getProviderClass()</code> in order to load the class.
	*
	* @param type Base class / Service interface of the factory to
	* instantiate.
	*
	* @param className Name of the concrete class corresponding to the
	* service provider
	*
	* @param cl ClassLoader to use to load the class, null means to use
	* the bootstrap ClassLoader
	*
	* @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 <T> T newInstance(Class<T> type, String className, ClassLoader cl,
	boolean doFallback, boolean useBSClsLoader)
	throws DatatypeConfigurationException
	{
	assert type != null;

	// make sure we have access to restricted packages
	if (System.getSecurityManager() != null) {
	if (className != null && className.startsWith(DEFAULT_PACKAGE)) {
	cl = null;
	useBSClsLoader = true;
	}
	}

	try {
	Class<?> providerClass = getProviderClass(className, cl, doFallback, useBSClsLoader);
	if (!type.isAssignableFrom(providerClass)) {
	throw new ClassCastException(className + " cannot be cast to " + type.getName());
	}
	Object instance = providerClass.newInstance();
	if (debug) { // Extra check to avoid computing cl strings
	dPrint("created new instance of " + providerClass +
	" using ClassLoader: " + cl);
	}
	return type.cast(instance);
	}
	catch (ClassNotFoundException x) {
	throw new DatatypeConfigurationException(
	"Provider " + className + " not found", x);
	}
	catch (Exception x) {
	throw new DatatypeConfigurationException(
	"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 type Base class / Service interface of the
	* factory to find.
	* @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 <T> T find(Class<T> type, String fallbackClassName)
	throws DatatypeConfigurationException
	{
	final String factoryId = type.getName();
	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(type, systemProp, null, true);
	}
	}
	catch (SecurityException se) {
	if (debug) se.printStackTrace();
	}

	// try to read from $java.home/lib/jaxp.properties
	try {
	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));
	}
	}
	}
	}
	final String factoryClassName = cacheProps.getProperty(factoryId);

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

	// Try Jar Service Provider Mechanism
	final T provider = findServiceProvider(type);
	if (provider != null) {
	return provider;
	}
	if (fallbackClassName == null) {
	throw new DatatypeConfigurationException(
	"Provider for " + factoryId + " cannot be found");
	}

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

	/*
	* Try to find provider using the ServiceLoader API
	*
	* @param type Base class / Service interface of the factory to find.
	*
	* @return instance of provider class if found or null
	*/
	private static <T> T findServiceProvider(final Class<T> type)
	throws DatatypeConfigurationException
	{
	try {
	return AccessController.doPrivileged(new PrivilegedAction<T>() {
	public T run() {
	final ServiceLoader<T> serviceLoader = ServiceLoader.load(type);
	final Iterator<T> iterator = serviceLoader.iterator();
	if (iterator.hasNext()) {
	return iterator.next();
	} else {
	return null;
	}
	}
	});
	} catch(ServiceConfigurationError e) {
	final DatatypeConfigurationException error =
	new DatatypeConfigurationException(
	"Provider for " + type + " cannot be found", e);
	throw error;
	}
	}

	}