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/* * Copyright (c) 2000, 2017, 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. */ // XMLReaderFactory.java - factory for creating a new reader. // http://www.saxproject.org // Written by David Megginson // and by David Brownell // NO WARRANTY! This class is in the Public Domain. // $Id: XMLReaderFactory.java,v 1.2.2.1 2005/07/31 22:48:08 jeffsuttor Exp $ package org.xml.sax.helpers; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.security.AccessController; import java.security.PrivilegedAction; import java.util.Iterator; import java.util.Objects; import java.util.ServiceConfigurationError; import java.util.ServiceLoader; import jdk.xml.internal.SecuritySupport; import org.xml.sax.SAXException; import org.xml.sax.XMLReader; /** * Factory for creating an XML reader. * * <blockquote> * <em>This module, both source code and documentation, is in the * Public Domain, and comes with <strong>NO WARRANTY</strong>.</em> * See <a href='http://www.saxproject.org'>http://www.saxproject.org</a> * for further information. * </blockquote> * * <p>This class contains static methods for creating an XML reader * from an explicit class name, or based on runtime defaults: * * <pre> * try { * XMLReader myReader = XMLReaderFactory.createXMLReader(); * } catch (SAXException e) { * System.err.println(e.getMessage()); * } * </pre> * * <p><strong>Note to Distributions bundled with parsers:</strong> * You should modify the implementation of the no-arguments * <em>createXMLReader</em> to handle cases where the external * configuration mechanisms aren't set up. That method should do its * best to return a parser when one is in the class path, even when * nothing bound its class name to {@code org.xml.sax.driver} so * those configuration mechanisms would see it. * * @since 1.4, SAX 2.0 * @author David Megginson, David Brownell * @version 2.0.1 (sax2r2) * * @deprecated It is recommended to use {@link javax.xml.parsers.SAXParserFactory} * instead. */ @Deprecated(since = "9") final public class XMLReaderFactory { /** * Private constructor. * * <p>This constructor prevents the class from being instantiated. */ private XMLReaderFactory() { } private static final String property = "org.xml.sax.driver"; /** * Obtains a new instance of a {@link org.xml.sax.XMLReader}. * This method uses the following ordered lookup procedure to find and load * the {@link org.xml.sax.XMLReader} implementation class: * <ol> * <li>If the system property {@code org.xml.sax.driver} * has a value, that is used as an XMLReader class name. </li> * <li> * Use the service-provider loading facility, defined by the * {@link java.util.ServiceLoader} class, to attempt to locate and load an * implementation of the service {@link org.xml.sax.XMLReader} by using the * {@linkplain java.lang.Thread#getContextClassLoader() current thread's context class loader}. * If the context class loader is null, the * {@linkplain ClassLoader#getSystemClassLoader() system class loader} will * be used. * </li> * <li> * Deprecated. Look for a class name in the {@code META-INF/services/org.xml.sax.driver} * file in a jar file available to the runtime.</li> * <li> * <p> * Otherwise, the system-default implementation is returned. * </li> * </ol> * * @apiNote * The process that looks for a class name in the * {@code META-INF/services/org.xml.sax.driver} file in a jar file does not * conform to the specification of the service-provider loading facility * as defined in {@link java.util.ServiceLoader} and therefore does not * support modularization. It is deprecated as of Java SE 9 and subject to * removal in a future release. * * @return a new XMLReader. * @exception org.xml.sax.SAXException If no default XMLReader class * can be identified and instantiated. * @see #createXMLReader(java.lang.String) */ public static XMLReader createXMLReader() throws SAXException { String className = null; ClassLoader cl = SecuritySupport.getClassLoader(); // 1. try the JVM-instance-wide system property try { className = SecuritySupport.getSystemProperty(property); } catch (RuntimeException e) { /* continue searching */ } // 2. try the ServiceLoader if (className == null) { final XMLReader provider = findServiceProvider(XMLReader.class, cl); if (provider != null) { return provider; } } // 3. try META-INF/services/org.xml.sax.driver. This old process allows // legacy providers to be found if (className == null) { className = jarLookup(cl); } // 4. Distro-specific fallback if (className == null) { return new com.sun.org.apache.xerces.internal.parsers.SAXParser(); } return loadClass(cl, className); } /** * Attempt to create an XML reader from a class name. * * <p>Given a class name, this method attempts to load * and instantiate the class as an XML reader. * * <p>Note that this method will not be usable in environments where * the caller (perhaps an applet) is not permitted to load classes * dynamically. * * @return A new XML reader. * @exception org.xml.sax.SAXException If the class cannot be * loaded, instantiated, and cast to XMLReader. * @see #createXMLReader() */ public static XMLReader createXMLReader(String className) throws SAXException { return loadClass(SecuritySupport.getClassLoader(), className); } private static XMLReader loadClass(ClassLoader loader, String className) throws SAXException { try { return NewInstance.newInstance(XMLReader.class, loader, className); } catch (ClassNotFoundException e1) { throw new SAXException("SAX2 driver class " + className + " not found", e1); } catch (IllegalAccessException e2) { throw new SAXException("SAX2 driver class " + className + " found but cannot be loaded", e2); } catch (InstantiationException e3) { throw new SAXException("SAX2 driver class " + className + " loaded but cannot be instantiated (no empty public constructor?)", e3); } catch (ClassCastException e4) { throw new SAXException("SAX2 driver class " + className + " does not implement XMLReader", e4); } } /** * Locates a provider by directly reading the jar service file. * @param loader the ClassLoader to be used to read the service file * @return the name of the provider, or null if nothing is found */ private static String jarLookup(final ClassLoader loader) { final ClassLoader cl = Objects.requireNonNull(loader); String clsFromJar = null; String service = "META-INF/services/" + property; InputStream in; BufferedReader reader; try { in = SecuritySupport.getResourceAsStream(cl, service); // If no provider found then try the current ClassLoader if (in == null) { in = SecuritySupport.getResourceAsStream(null, service); } if (in != null) { reader = new BufferedReader(new InputStreamReader(in, "UTF8")); clsFromJar = reader.readLine(); in.close(); } } catch (IOException e) { } return clsFromJar; } /* * 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, final ClassLoader loader) throws SAXException { ClassLoader cl = Objects.requireNonNull(loader); try { return AccessController.doPrivileged((PrivilegedAction<T>) () -> { final ServiceLoader<T> serviceLoader; serviceLoader = ServiceLoader.load(type, cl); final Iterator<T> iterator = serviceLoader.iterator(); if (iterator.hasNext()) { return iterator.next(); } else { return null; } }); } catch (ServiceConfigurationError e) { final RuntimeException x = new RuntimeException("Provider for " + type + " cannot be created", e); throw new SAXException("Provider for " + type + " cannot be created", x); } } }