- /*
- * Copyright 2001-2004 The Apache Software Foundation.
- *
- * Licensed 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: ObjectFactory.java,v 1.2 2004/03/11 00:58:39 bhakti Exp $
- */
-
- package com.sun.org.apache.xpath.internal.functions;
-
- import java.io.InputStream;
- import java.io.IOException;
- import java.io.File;
- import java.io.FileInputStream;
-
- import java.util.Properties;
- import java.io.BufferedReader;
- import java.io.InputStreamReader;
-
- /**
- * This class is duplicated for each JAXP subpackage so keep it in sync.
- * It is package private and therefore is not exposed as part of the JAXP
- * API.
- * <p>
- * This code is designed to implement the JAXP 1.1 spec pluggability
- * feature and is designed to run on JDK version 1.1 and
- * later, and to compile on JDK 1.2 and onward.
- * The code also runs both as part of an unbundled jar file and
- * when bundled as part of the JDK.
- * <p>
- * This class was moved from the <code>javax.xml.parsers.ObjectFactory</code>
- * class and modified to be used as a general utility for creating objects
- * dynamically.
- *
- * @version $Id: ObjectFactory.java,v 1.2 2004/03/11 00:58:39 bhakti Exp $
- */
- class ObjectFactory {
-
- //
- // Constants
- //
-
- // name of default properties file to look for in JDK's jre/lib directory
- private static final String DEFAULT_PROPERTIES_FILENAME =
- "xalan.properties";
-
- private static final String SERVICES_PATH = "META-INF/services/";
-
- /** Set to true for debugging */
- private static final boolean DEBUG = false;
-
- /** cache the contents of the xalan.properties file.
- * Until an attempt has been made to read this file, this will
- * be null; if the file does not exist or we encounter some other error
- * during the read, this will be empty.
- */
- private static Properties fXalanProperties = null;
-
- /***
- * Cache the time stamp of the xalan.properties file so
- * that we know if it's been modified and can invalidate
- * the cache when necessary.
- */
- private static long fLastModified = -1;
-
- //
- // Public static methods
- //
-
- /**
- * Finds the implementation Class object in the specified order. The
- * specified order is the following:
- * <ol>
- * <li>query the system property using <code>System.getProperty</code>
- * <li>read <code>META-INF/services/<i>factoryId</i></code> file
- * <li>use fallback classname
- * </ol>
- *
- * @return instance 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.
- *
- * @exception ObjectFactory.ConfigurationError
- */
- static Object createObject(String factoryId, String fallbackClassName)
- throws ConfigurationError {
- return createObject(factoryId, null, fallbackClassName);
- } // createObject(String,String):Object
-
- /**
- * Finds the implementation Class object in the specified order. The
- * specified order is the following:
- * <ol>
- * <li>query the system property using <code>System.getProperty</code>
- * <li>read <code>$java.home/lib/<i>propertiesFilename</i></code> file
- * <li>read <code>META-INF/services/<i>factoryId</i></code> file
- * <li>use fallback classname
- * </ol>
- *
- * @return instance of factory, never null
- *
- * @param factoryId Name of the factory to find, same as
- * a property name
- * @param propertiesFilename The filename in the $java.home/lib directory
- * of the properties file. If none specified,
- * ${java.home}/lib/xalan.properties will be used.
- * @param fallbackClassName Implementation class name, if nothing else
- * is found. Use null to mean no fallback.
- *
- * @exception ObjectFactory.ConfigurationError
- */
- static Object createObject(String factoryId,
- String propertiesFilename,
- String fallbackClassName)
- throws ConfigurationError
- {
- Class factoryClass = lookUpFactoryClass(factoryId,
- propertiesFilename,
- fallbackClassName);
-
- if (factoryClass == null) {
- throw new ConfigurationError(
- "Provider for " + factoryId + " cannot be found", null);
- }
-
- try{
- Object instance = factoryClass.newInstance();
- debugPrintln("created new instance of factory " + factoryId);
- return instance;
- } catch (Exception x) {
- throw new ConfigurationError(
- "Provider for factory " + factoryId
- + " could not be instantiated: " + x, x);
- }
- } // createObject(String,String,String):Object
-
- /**
- * Finds the implementation Class object in the specified order. The
- * specified order is the following:
- * <ol>
- * <li>query the system property using <code>System.getProperty</code>
- * <li>read <code>$java.home/lib/<i>propertiesFilename</i></code> file
- * <li>read <code>META-INF/services/<i>factoryId</i></code> file
- * <li>use fallback classname
- * </ol>
- *
- * @return Class object of factory, never null
- *
- * @param factoryId Name of the factory to find, same as
- * a property name
- * @param propertiesFilename The filename in the $java.home/lib directory
- * of the properties file. If none specified,
- * ${java.home}/lib/xalan.properties will be used.
- * @param fallbackClassName Implementation class name, if nothing else
- * is found. Use null to mean no fallback.
- *
- * @exception ObjectFactory.ConfigurationError
- */
- static Class lookUpFactoryClass(String factoryId)
- throws ConfigurationError
- {
- return lookUpFactoryClass(factoryId, null, null);
- } // lookUpFactoryClass(String):Class
-
- /**
- * Finds the implementation Class object in the specified order. The
- * specified order is the following:
- * <ol>
- * <li>query the system property using <code>System.getProperty</code>
- * <li>read <code>$java.home/lib/<i>propertiesFilename</i></code> file
- * <li>read <code>META-INF/services/<i>factoryId</i></code> file
- * <li>use fallback classname
- * </ol>
- *
- * @return Class object that provides factory service, never null
- *
- * @param factoryId Name of the factory to find, same as
- * a property name
- * @param propertiesFilename The filename in the $java.home/lib directory
- * of the properties file. If none specified,
- * ${java.home}/lib/xalan.properties will be used.
- * @param fallbackClassName Implementation class name, if nothing else
- * is found. Use null to mean no fallback.
- *
- * @exception ObjectFactory.ConfigurationError
- */
- static Class lookUpFactoryClass(String factoryId,
- String propertiesFilename,
- String fallbackClassName)
- throws ConfigurationError
- {
- String factoryClassName = lookUpFactoryClassName(factoryId,
- propertiesFilename,
- fallbackClassName);
- ClassLoader cl = findClassLoader();
-
- if (factoryClassName == null) {
- factoryClassName = fallbackClassName;
- }
-
- // assert(className != null);
- try{
- Class providerClass = findProviderClass(factoryClassName,
- cl,
- true);
- debugPrintln("created new instance of " + providerClass +
- " using ClassLoader: " + cl);
- return providerClass;
- } catch (ClassNotFoundException x) {
- throw new ConfigurationError(
- "Provider " + factoryClassName + " not found", x);
- } catch (Exception x) {
- throw new ConfigurationError(
- "Provider "+factoryClassName+" could not be instantiated: "+x,
- x);
- }
- } // lookUpFactoryClass(String,String,String):Class
-
- /**
- * Finds the name of the required implementation class in the specified
- * order. The specified order is the following:
- * <ol>
- * <li>query the system property using <code>System.getProperty</code>
- * <li>read <code>$java.home/lib/<i>propertiesFilename</i></code> file
- * <li>read <code>META-INF/services/<i>factoryId</i></code> file
- * <li>use fallback classname
- * </ol>
- *
- * @return name of class that provides factory service, never null
- *
- * @param factoryId Name of the factory to find, same as
- * a property name
- * @param propertiesFilename The filename in the $java.home/lib directory
- * of the properties file. If none specified,
- * ${java.home}/lib/xalan.properties will be used.
- * @param fallbackClassName Implementation class name, if nothing else
- * is found. Use null to mean no fallback.
- *
- * @exception ObjectFactory.ConfigurationError
- */
- static String lookUpFactoryClassName(String factoryId,
- String propertiesFilename,
- String fallbackClassName)
- {
- SecuritySupport ss = SecuritySupport.getInstance();
-
- // Use the system property first
- try {
- String systemProp = ss.getSystemProperty(factoryId);
- if (systemProp != null) {
- debugPrintln("found system property, value=" + systemProp);
- return systemProp;
- }
- } catch (SecurityException se) {
- // Ignore and continue w/ next location
- }
-
- // Try to read from propertiesFilename, or
- // $java.home/lib/xalan.properties
- String factoryClassName = null;
- // no properties file name specified; use
- // $JAVA_HOME/lib/xalan.properties:
- if (propertiesFilename == null) {
- File propertiesFile = null;
- boolean propertiesFileExists = false;
- try {
- String javah = ss.getSystemProperty("java.home");
- propertiesFilename = javah + File.separator +
- "lib" + File.separator + DEFAULT_PROPERTIES_FILENAME;
- propertiesFile = new File(propertiesFilename);
- propertiesFileExists = ss.getFileExists(propertiesFile);
- } catch (SecurityException e) {
- // try again...
- fLastModified = -1;
- fXalanProperties = null;
- }
-
- synchronized (ObjectFactory.class) {
- boolean loadProperties = false;
- try {
- // file existed last time
- if(fLastModified >= 0) {
- if(propertiesFileExists &&
- (fLastModified < (fLastModified = ss.getLastModified(propertiesFile)))) {
- loadProperties = true;
- } else {
- // file has stopped existing...
- if(!propertiesFileExists) {
- fLastModified = -1;
- fXalanProperties = null;
- } // else, file wasn't modified!
- }
- } else {
- // file has started to exist:
- if(propertiesFileExists) {
- loadProperties = true;
- fLastModified = ss.getLastModified(propertiesFile);
- } // else, nothing's changed
- }
- if(loadProperties) {
- // must never have attempted to read xalan.properties
- // before (or it's outdeated)
- fXalanProperties = new Properties();
- FileInputStream fis =
- ss.getFileInputStream(propertiesFile);
- fXalanProperties.load(fis);
- fis.close();
- }
- } catch (Exception x) {
- fXalanProperties = null;
- fLastModified = -1;
- // assert(x instanceof FileNotFoundException
- // || x instanceof SecurityException)
- // In both cases, ignore and continue w/ next location
- }
- }
- if(fXalanProperties != null) {
- factoryClassName = fXalanProperties.getProperty(factoryId);
- }
- } else {
- try {
- FileInputStream fis =
- ss.getFileInputStream(new File(propertiesFilename));
- Properties props = new Properties();
- props.load(fis);
- fis.close();
- factoryClassName = props.getProperty(factoryId);
- } catch (Exception x) {
- // assert(x instanceof FileNotFoundException
- // || x instanceof SecurityException)
- // In both cases, ignore and continue w/ next location
- }
- }
- if (factoryClassName != null) {
- debugPrintln("found in " + propertiesFilename + ", value="
- + factoryClassName);
- return factoryClassName;
- }
-
- // Try Jar Service Provider Mechanism
- return findJarServiceProviderName(factoryId);
- } // lookUpFactoryClass(String,String):String
-
- //
- // Private static methods
- //
-
- /** Prints a message to standard error if debugging is enabled. */
- private static void debugPrintln(String msg) {
- if (DEBUG) {
- System.err.println("JAXP: " + msg);
- }
- } // debugPrintln(String)
-
- /**
- * Figure out which ClassLoader to use. For JDK 1.2 and later use
- * the context ClassLoader.
- */
- static ClassLoader findClassLoader()
- throws ConfigurationError
- {
- SecuritySupport ss = SecuritySupport.getInstance();
-
- // Figure out which ClassLoader to use for loading the provider
- // class. If there is a Context ClassLoader then use it.
- ClassLoader context = ss.getContextClassLoader();
- ClassLoader system = ss.getSystemClassLoader();
-
- ClassLoader chain = system;
- while (true) {
- if (context == chain) {
- // Assert: we are on JDK 1.1 or we have no Context ClassLoader
- // or any Context ClassLoader in chain of system classloader
- // (including extension ClassLoader) so extend to widest
- // ClassLoader (always look in system ClassLoader if Xalan
- // is in boot/extension/system classpath and in current
- // ClassLoader otherwise); normal classloaders delegate
- // back to system ClassLoader first so this widening doesn't
- // change the fact that context ClassLoader will be consulted
- ClassLoader current = ObjectFactory.class.getClassLoader();
-
- chain = system;
- while (true) {
- if (current == chain) {
- // Assert: Current ClassLoader in chain of
- // boot/extension/system ClassLoaders
- return system;
- }
- if (chain == null) {
- break;
- }
- chain = ss.getParentClassLoader(chain);
- }
-
- // Assert: Current ClassLoader not in chain of
- // boot/extension/system ClassLoaders
- return current;
- }
-
- if (chain == null) {
- // boot ClassLoader reached
- break;
- }
-
- // Check for any extension ClassLoaders in chain up to
- // boot ClassLoader
- chain = ss.getParentClassLoader(chain);
- };
-
- // Assert: Context ClassLoader not in chain of
- // boot/extension/system ClassLoaders
- return context;
- } // findClassLoader():ClassLoader
-
- /**
- * Create an instance of a class using the specified ClassLoader
- */
- static Object newInstance(String className, ClassLoader cl,
- boolean doFallback)
- throws ConfigurationError
- {
- // assert(className != null);
- try{
- Class providerClass = findProviderClass(className, cl, doFallback);
- Object instance = providerClass.newInstance();
- debugPrintln("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);
- }
- }
-
- /**
- * Find a Class using the specified ClassLoader
- */
- static Class findProviderClass(String className, ClassLoader cl,
- boolean doFallback)
- throws ClassNotFoundException, ConfigurationError
- {
- //throw security exception if the calling thread is not allowed to access the
- //class. Restrict the access to the package classes as specified in java.security policy.
- SecurityManager security = System.getSecurityManager();
- try{
- if (security != null){
- final int lastDot = className.lastIndexOf(".");
- String packageName = className;
- if (lastDot != -1)
- packageName = className.substring(0, lastDot);
- security.checkPackageAccess(packageName);
- }
- }catch(SecurityException e){
- throw e;
- }
-
- Class providerClass;
- if (cl == null) {
- // XXX Use the bootstrap ClassLoader. There is no way to
- // load a class using the bootstrap ClassLoader that works
- // in both JDK 1.1 and Java 2. However, this should still
- // work b/c the following should be true:
- //
- // (cl == null) iff current ClassLoader == null
- //
- // Thus Class.forName(String) will use the current
- // ClassLoader which will be the bootstrap ClassLoader.
- providerClass = Class.forName(className);
- } else {
- try {
- providerClass = cl.loadClass(className);
- } catch (ClassNotFoundException x) {
- if (doFallback) {
- // Fall back to current classloader
- ClassLoader current = ObjectFactory.class.getClassLoader();
- if (current == null) {
- providerClass = Class.forName(className);
- } else if (cl != current) {
- cl = current;
- providerClass = cl.loadClass(className);
- } else {
- throw x;
- }
- } else {
- throw x;
- }
- }
- }
-
- return providerClass;
- }
-
- /**
- * Find the name of service provider using Jar Service Provider Mechanism
- *
- * @return instance of provider class if found or null
- */
- private static String findJarServiceProviderName(String factoryId)
- {
- SecuritySupport ss = SecuritySupport.getInstance();
- String serviceId = SERVICES_PATH + factoryId;
- InputStream is = null;
-
- // First try the Context ClassLoader
- ClassLoader cl = findClassLoader();
-
- is = ss.getResourceAsStream(cl, serviceId);
-
- // If no provider found then try the current ClassLoader
- if (is == null) {
- ClassLoader current = ObjectFactory.class.getClassLoader();
- if (cl != current) {
- cl = current;
- is = ss.getResourceAsStream(cl, serviceId);
- }
- }
-
- if (is == null) {
- // No provider found
- return null;
- }
-
- debugPrintln("found jar resource=" + serviceId +
- " using ClassLoader: " + cl);
-
- // Read the service provider name in UTF-8 as specified in
- // the jar spec. Unfortunately this fails in Microsoft
- // VJ++, which does not implement the UTF-8
- // encoding. Theoretically, we should simply let it fail in
- // that case, since the JVM is obviously broken if it
- // doesn't support such a basic standard. But since there
- // are still some users attempting to use VJ++ for
- // development, we have dropped in a fallback which makes a
- // second attempt using the platform's default encoding. In
- // VJ++ this is apparently ASCII, which is a subset of
- // UTF-8... and since the strings we'll be reading here are
- // also primarily limited to the 7-bit ASCII range (at
- // least, in English versions), this should work well
- // enough to keep us on the air until we're ready to
- // officially decommit from VJ++. [Edited comment from
- // jkesselm]
- 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)) {
- debugPrintln("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 factoryClassName;
- }
-
- // No provider found
- return null;
- }
-
- //
- // Classes
- //
-
- /**
- * A configuration error.
- */
- static class ConfigurationError
- extends Error {
-
- //
- // Data
- //
-
- /** Exception. */
- private Exception exception;
-
- //
- // Constructors
- //
-
- /**
- * Construct a new instance with the specified detail string and
- * exception.
- */
- ConfigurationError(String msg, Exception x) {
- super(msg);
- this.exception = x;
- } // <init>(String,Exception)
-
- //
- // Public methods
- //
-
- /** Returns the exception associated to this error. */
- Exception getException() {
- return exception;
- } // getException():Exception
-
- } // class ConfigurationError
-
- } // class ObjectFactory