android-platform-libcore/luni/src/main/java/javax/xml/datatype/FactoryFinder.java - nest-cam/4320010/android-platform-libcore - Git at Google

 /*
  * Licensed to the Apache Software Foundation (ASF) under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
  * The ASF licenses this file to You under the Apache License, Version 2.0
  * (the "License"); you may not use this file except in compliance with
  * the License.  You may obtain a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 // $Id: FactoryFinder.java 670432 2008-06-23 02:02:08Z mrglavas $

 package javax.xml.datatype;

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

 /**
  * <p>Implement pluggabile 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 <a href="mailto:Jeff.Suttor@Sun.com">Jeff Suttor</a>
  * @version $Revision: 670432 $, $Date: 2008-06-22 19:02:08 -0700 (Sun, 22 Jun 2008) $
  * @since 1.5
  */
 final class FactoryFinder {

     /**
      * <p>Name of class to display in output messages.</p>
      */
     private static final String CLASS_NAME = "javax.xml.datatype.FactoryFinder";

     /**
      * <p>Debug flag to trace loading process.</p>
      */
     private static boolean debug = false;

     /**
      * <p>Cache properties for performance.</p>
      */
     private static Properties cacheProps = new Properties();

     /**
      * <p>First time requires initialization overhead.</p>
      */
     private static boolean firstTime = true;

     /**
      * Default columns per line.
      */
     private static final int DEFAULT_LINE_LENGTH = 80;

     /**
      * <p>Check to see if debugging enabled by property.</p>
      *
      * <p>Use try/catch block to support applets, which throws
      * SecurityException out of this code.</p>
      *
      */
     static {
         try {
             String val = SecuritySupport.getSystemProperty("jaxp.debug");
             // Allow simply setting the prop to turn on debug
             debug = val != null && (! "false".equals(val));
         } catch (Exception x) {
             debug = false;
         }
     }

     private FactoryFinder() {}

     /**
      * <p>Output debugging messages.</p>
      *
      * @param msg <code>String</code> to print to <code>stderr</code>.
      */
     private static void debugPrintln(String msg) {
         if (debug) {
             System.err.println(
                 CLASS_NAME
                 + ":"
                 + msg);
         }
     }

     /**
      * <p>Find the appropriate <code>ClassLoader</code> to use.</p>
      *
      * <p>The context ClassLoader is prefered.</p>
      *
      * @return <code>ClassLoader</code> to use.
      *
      * @throws ConfigurationError If a valid <code>ClassLoader</code> cannot be identified.
      */
     private static ClassLoader findClassLoader()
         throws ConfigurationError {
         ClassLoader classLoader;

         // Figure out which ClassLoader to use for loading the provider
         // class.  If there is a Context ClassLoader then use it.

         classLoader = SecuritySupport.getContextClassLoader();

         if (debug) debugPrintln(
             "Using context class loader: "
             + classLoader);

         if (classLoader == null) {
             // if we have no Context ClassLoader
             // so use the current ClassLoader
             classLoader = FactoryFinder.class.getClassLoader();
             if (debug) debugPrintln(
                 "Using the class loader of FactoryFinder: "
                 + classLoader);
         }

         return classLoader;
     }

     /**
      * <p>Create an instance of a class using the specified ClassLoader.</p>
      *
      * @param className Name of class to create.
      * @param classLoader ClassLoader to use to create named class.
      *
      * @return New instance of specified class created using the specified ClassLoader.
      *
      * @throws ConfigurationError If class could not be created.
      */
     static Object newInstance(
         String className,
         ClassLoader classLoader)
         throws ConfigurationError {

         try {
             Class spiClass;
             if (classLoader == null) {
                 spiClass = Class.forName(className);
             } else {
                 spiClass = classLoader.loadClass(className);
             }

             if (debug) {
                 debugPrintln("Loaded " + className + " from " + which(spiClass));
             }

             return spiClass.newInstance();
         } 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.
      * Package private so this code can be shared.
      *
      * @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.
      *
      * @return Class Object of factory, never null
      *
      * @throws ConfigurationError If Class cannot be found.
      */
     static Object find(String factoryId, String fallbackClassName)
         throws ConfigurationError {

         ClassLoader classLoader = findClassLoader();

         // Use the system property first
         try {
             String systemProp = SecuritySupport.getSystemProperty(factoryId);
             if (systemProp != null && systemProp.length() > 0) {
                 if (debug) debugPrintln("found " + systemProp + " in the system property " + factoryId);
                 return newInstance(systemProp, classLoader);
             }
         } catch (SecurityException se) {
             ; // NOP, explicitly ignore SecurityException
         }

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

             if (factoryClassName != null) {
                 return newInstance(factoryClassName, classLoader);
             }
         } 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);
         }

         if (debug) debugPrintln("loaded from fallback value: " + fallbackClassName);
         return newInstance(fallbackClassName, classLoader);
     }

     /*
      * 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 = SecuritySupport.getContextClassLoader();
         if (cl != null) {
             is = SecuritySupport.getResourceAsStream(cl, serviceId);

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

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

         if (debug) debugPrintln("found jar resource=" + serviceId +
                " using ClassLoader: " + cl);

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

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

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

             return newInstance(factoryClassName, cl);
         }

         // No provider found
         return null;
     }

     /**
      * <p>Configuration Error.</p>
      */
     static class ConfigurationError extends Error {

         private static final long serialVersionUID = -3644413026244211347L;

         /**
          * <p>Exception that caused the error.</p>
          */
         private Exception exception;

         /**
          * <p>Construct a new instance with the specified detail string and
          * exception.</p>
          *
          * @param msg Detail message for this error.
          * @param x Exception that caused the error.
          */
         ConfigurationError(String msg, Exception x) {
             super(msg);
             this.exception = x;
         }

         /**
          * <p>Get the Exception that caused the error.</p>
          *
          * @return Exception that caused the error.
          */
         Exception getException() {
             return exception;
         }
     }


     /**
      * Returns the location where the given Class is loaded from.
      *
      * @param clazz Class to find load location.
      *
      * @return Location where class would be loaded from.
      */
     private static String which(Class clazz) {
         try {
             String classnameAsResource = clazz.getName().replace('.', '/') + ".class";

             ClassLoader loader = clazz.getClassLoader();

             URL it;

             if (loader != null) {
                 it = loader.getResource(classnameAsResource);
             } else {
                 it = ClassLoader.getSystemResource(classnameAsResource);
             }

             if (it != null) {
                 return it.toString();
             }
         }
         // The VM ran out of memory or there was some other serious problem. Re-throw.
         catch (VirtualMachineError vme) {
             throw vme;
         }
         // ThreadDeath should always be re-thrown
         catch (ThreadDeath td) {
             throw td;
         }
         catch (Throwable t) {
             // work defensively.
             if (debug) {
                 t.printStackTrace();
             }
         }
         return "unknown location";
     }
 }
	/*
	* Licensed to the Apache Software Foundation (ASF) under one or more
	* contributor license agreements. See the NOTICE file distributed with
	* this work for additional information regarding copyright ownership.
	* The ASF licenses this file to You under the Apache License, Version 2.0
	* (the "License"); you may not use this file except in compliance with
	* the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	// $Id: FactoryFinder.java 670432 2008-06-23 02:02:08Z mrglavas $

	package javax.xml.datatype;

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

	/**
	* <p>Implement pluggabile 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 <a href="mailto:Jeff.Suttor@Sun.com">Jeff Suttor</a>
	* @version $Revision: 670432 $, $Date: 2008-06-22 19:02:08 -0700 (Sun, 22 Jun 2008) $
	* @since 1.5
	*/
	final class FactoryFinder {

	/**
	* <p>Name of class to display in output messages.</p>
	*/
	private static final String CLASS_NAME = "javax.xml.datatype.FactoryFinder";

	/**
	* <p>Debug flag to trace loading process.</p>
	*/
	private static boolean debug = false;

	/**
	* <p>Cache properties for performance.</p>
	*/
	private static Properties cacheProps = new Properties();

	/**
	* <p>First time requires initialization overhead.</p>
	*/
	private static boolean firstTime = true;

	/**
	* Default columns per line.
	*/
	private static final int DEFAULT_LINE_LENGTH = 80;

	/**
	* <p>Check to see if debugging enabled by property.</p>
	*
	* <p>Use try/catch block to support applets, which throws
	* SecurityException out of this code.</p>
	*
	*/
	static {
	try {
	String val = SecuritySupport.getSystemProperty("jaxp.debug");
	// Allow simply setting the prop to turn on debug
	debug = val != null && (! "false".equals(val));
	} catch (Exception x) {
	debug = false;
	}
	}

	private FactoryFinder() {}

	/**
	* <p>Output debugging messages.</p>
	*
	* @param msg <code>String</code> to print to <code>stderr</code>.
	*/
	private static void debugPrintln(String msg) {
	if (debug) {
	System.err.println(
	CLASS_NAME
	+ ":"
	+ msg);
	}
	}

	/**
	* <p>Find the appropriate <code>ClassLoader</code> to use.</p>
	*
	* <p>The context ClassLoader is prefered.</p>
	*
	* @return <code>ClassLoader</code> to use.
	*
	* @throws ConfigurationError If a valid <code>ClassLoader</code> cannot be identified.
	*/
	private static ClassLoader findClassLoader()
	throws ConfigurationError {
	ClassLoader classLoader;

	// Figure out which ClassLoader to use for loading the provider
	// class. If there is a Context ClassLoader then use it.

	classLoader = SecuritySupport.getContextClassLoader();

	if (debug) debugPrintln(
	"Using context class loader: "
	+ classLoader);

	if (classLoader == null) {
	// if we have no Context ClassLoader
	// so use the current ClassLoader
	classLoader = FactoryFinder.class.getClassLoader();
	if (debug) debugPrintln(
	"Using the class loader of FactoryFinder: "
	+ classLoader);
	}

	return classLoader;
	}

	/**
	* <p>Create an instance of a class using the specified ClassLoader.</p>
	*
	* @param className Name of class to create.
	* @param classLoader ClassLoader to use to create named class.
	*
	* @return New instance of specified class created using the specified ClassLoader.
	*
	* @throws ConfigurationError If class could not be created.
	*/
	static Object newInstance(
	String className,
	ClassLoader classLoader)
	throws ConfigurationError {

	try {
	Class spiClass;
	if (classLoader == null) {
	spiClass = Class.forName(className);
	} else {
	spiClass = classLoader.loadClass(className);
	}

	if (debug) {
	debugPrintln("Loaded " + className + " from " + which(spiClass));
	}

	return spiClass.newInstance();
	} 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.
	* Package private so this code can be shared.
	*
	* @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.
	*
	* @return Class Object of factory, never null
	*
	* @throws ConfigurationError If Class cannot be found.
	*/
	static Object find(String factoryId, String fallbackClassName)
	throws ConfigurationError {

	ClassLoader classLoader = findClassLoader();

	// Use the system property first
	try {
	String systemProp = SecuritySupport.getSystemProperty(factoryId);
	if (systemProp != null && systemProp.length() > 0) {
	if (debug) debugPrintln("found " + systemProp + " in the system property " + factoryId);
	return newInstance(systemProp, classLoader);
	}
	} catch (SecurityException se) {
	; // NOP, explicitly ignore SecurityException
	}

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

	if (factoryClassName != null) {
	return newInstance(factoryClassName, classLoader);
	}
	} 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);
	}

	if (debug) debugPrintln("loaded from fallback value: " + fallbackClassName);
	return newInstance(fallbackClassName, classLoader);
	}

	/*
	* 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 = SecuritySupport.getContextClassLoader();
	if (cl != null) {
	is = SecuritySupport.getResourceAsStream(cl, serviceId);

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

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

	if (debug) debugPrintln("found jar resource=" + serviceId +
	" using ClassLoader: " + cl);

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

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

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

	return newInstance(factoryClassName, cl);
	}

	// No provider found
	return null;
	}

	/**
	* <p>Configuration Error.</p>
	*/
	static class ConfigurationError extends Error {

	private static final long serialVersionUID = -3644413026244211347L;

	/**
	* <p>Exception that caused the error.</p>
	*/
	private Exception exception;

	/**
	* <p>Construct a new instance with the specified detail string and
	* exception.</p>
	*
	* @param msg Detail message for this error.
	* @param x Exception that caused the error.
	*/
	ConfigurationError(String msg, Exception x) {
	super(msg);
	this.exception = x;
	}

	/**
	* <p>Get the Exception that caused the error.</p>
	*
	* @return Exception that caused the error.
	*/
	Exception getException() {
	return exception;
	}
	}



	/**
	* Returns the location where the given Class is loaded from.
	*
	* @param clazz Class to find load location.
	*
	* @return Location where class would be loaded from.
	*/
	private static String which(Class clazz) {
	try {
	String classnameAsResource = clazz.getName().replace('.', '/') + ".class";

	ClassLoader loader = clazz.getClassLoader();

	URL it;

	if (loader != null) {
	it = loader.getResource(classnameAsResource);
	} else {
	it = ClassLoader.getSystemResource(classnameAsResource);
	}

	if (it != null) {
	return it.toString();
	}
	}
	// The VM ran out of memory or there was some other serious problem. Re-throw.
	catch (VirtualMachineError vme) {
	throw vme;
	}
	// ThreadDeath should always be re-thrown
	catch (ThreadDeath td) {
	throw td;
	}
	catch (Throwable t) {
	// work defensively.
	if (debug) {
	t.printStackTrace();
	}
	}
	return "unknown location";
	}
	}