1 /* 2 * Copyright (c) 2004, 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package javax.xml.datatype; 27 28 import java.io.File; 29 import java.security.AccessController; 30 import java.security.PrivilegedAction; 31 import java.util.Iterator; 32 import java.util.Properties; 33 import java.util.ServiceConfigurationError; 34 import java.util.ServiceLoader; 35 36 /** 37 * <p>Implements pluggable Datatypes.</p> 38 * 39 * <p>This class is duplicated for each JAXP subpackage so keep it in 40 * sync. It is package private for secure class loading.</p> 41 * 42 * @author Santiago.PericasGeertsen@sun.com 43 */ 44 class FactoryFinder { 45 private static final String DEFAULT_PACKAGE = "com.sun.org.apache.xerces.internal"; 46 47 /** 48 * Internal debug flag. 49 */ 50 private static boolean debug = false; 51 52 /** 53 * Cache for properties in java.home/conf/jaxp.properties 54 */ 55 private final static Properties cacheProps = new Properties(); 56 57 /** 58 * Flag indicating if properties from java.home/conf/jaxp.properties 59 * have been cached. 60 */ 61 private static volatile boolean firstTime = true; 62 63 /** 64 * Security support class use to check access control before 65 * getting certain system resources. 66 */ 67 private final static SecuritySupport ss = new SecuritySupport(); 68 69 // Define system property "jaxp.debug" to get output 70 static { 71 // Use try/catch block to support applets, which throws 72 // SecurityException out of this code. 73 try { 74 String val = ss.getSystemProperty("jaxp.debug"); 75 // Allow simply setting the prop to turn on debug 76 debug = val != null && !"false".equals(val); 77 } 78 catch (SecurityException se) { 79 debug = false; 80 } 81 } 82 83 private static void dPrint(String msg) { 84 if (debug) { 85 System.err.println("JAXP: " + msg); 86 } 87 } 88 89 /** 90 * Attempt to load a class using the class loader supplied. If that fails 91 * and fall back is enabled, the current (i.e. bootstrap) class loader is 92 * tried. 93 * 94 * If the class loader supplied is <code>null</code>, first try using the 95 * context class loader followed by the current (i.e. bootstrap) class 96 * loader. 97 * 98 * Use bootstrap classLoader if cl = null and useBSClsLoader is true 99 */ 100 static private Class<?> getProviderClass(String className, ClassLoader cl, 101 boolean doFallback, boolean useBSClsLoader) throws ClassNotFoundException 102 { 103 try { 104 if (cl == null) { 105 if (useBSClsLoader) { 106 return Class.forName(className, false, FactoryFinder.class.getClassLoader()); 107 } else { 108 cl = ss.getContextClassLoader(); 109 if (cl == null) { 110 throw new ClassNotFoundException(); 111 } 112 else { 113 return Class.forName(className, false, cl); 114 } 115 } 116 } 117 else { 118 return Class.forName(className, false, cl); 119 } 120 } 121 catch (ClassNotFoundException e1) { 122 if (doFallback) { 123 // Use current class loader - should always be bootstrap CL 124 return Class.forName(className, false, FactoryFinder.class.getClassLoader()); 125 } 126 else { 127 throw e1; 128 } 129 } 130 } 131 132 /** 133 * Create an instance of a class. Delegates to method 134 * <code>getProviderClass()</code> in order to load the class. 135 * 136 * @param type Base class / Service interface of the factory to 137 * instantiate. 138 * 139 * @param className Name of the concrete class corresponding to the 140 * service provider 141 * 142 * @param cl <code>ClassLoader</code> used to load the factory class. If <code>null</code> 143 * current <code>Thread</code>'s context classLoader is used to load the factory class. 144 * 145 * @param doFallback True if the current ClassLoader should be tried as 146 * a fallback if the class is not found using cl 147 */ 148 static <T> T newInstance(Class<T> type, String className, ClassLoader cl, boolean doFallback) 149 throws DatatypeConfigurationException 150 { 151 return newInstance(type, className, cl, doFallback, false); 152 } 153 154 /** 155 * Create an instance of a class. Delegates to method 156 * <code>getProviderClass()</code> in order to load the class. 157 * 158 * @param type Base class / Service interface of the factory to 159 * instantiate. 160 * 161 * @param className Name of the concrete class corresponding to the 162 * service provider 163 * 164 * @param cl ClassLoader to use to load the class, null means to use 165 * the bootstrap ClassLoader 166 * 167 * @param doFallback True if the current ClassLoader should be tried as 168 * a fallback if the class is not found using cl 169 * 170 * @param useBSClsLoader True if cl=null actually meant bootstrap classLoader. This parameter 171 * is needed since DocumentBuilderFactory/SAXParserFactory defined null as context classLoader. 172 */ 173 static <T> T newInstance(Class<T> type, String className, ClassLoader cl, 174 boolean doFallback, boolean useBSClsLoader) 175 throws DatatypeConfigurationException 176 { 177 assert type != null; 178 179 // make sure we have access to restricted packages 180 if (System.getSecurityManager() != null) { 181 if (className != null && className.startsWith(DEFAULT_PACKAGE)) { 182 cl = null; 183 useBSClsLoader = true; 184 } 185 } 186 187 try { 188 Class<?> providerClass = getProviderClass(className, cl, doFallback, useBSClsLoader); 189 if (!type.isAssignableFrom(providerClass)) { 190 throw new ClassCastException(className + " cannot be cast to " + type.getName()); 191 } 192 Object instance = providerClass.newInstance(); 193 if (debug) { // Extra check to avoid computing cl strings 194 dPrint("created new instance of " + providerClass + 195 " using ClassLoader: " + cl); 196 } 197 return type.cast(instance); 198 } 199 catch (ClassNotFoundException x) { 200 throw new DatatypeConfigurationException( 201 "Provider " + className + " not found", x); 202 } 203 catch (Exception x) { 204 throw new DatatypeConfigurationException( 205 "Provider " + className + " could not be instantiated: " + x, 206 x); 207 } 208 } 209 210 /** 211 * Finds the implementation Class object in the specified order. Main 212 * entry point. 213 * @return Class object of factory, never null 214 * 215 * @param type Base class / Service interface of the 216 * factory to find. 217 * @param fallbackClassName Implementation class name, if nothing else 218 * is found. Use null to mean no fallback. 219 * 220 * Package private so this code can be shared. 221 */ 222 static <T> T find(Class<T> type, String fallbackClassName) 223 throws DatatypeConfigurationException 224 { 225 final String factoryId = type.getName(); 226 dPrint("find factoryId =" + factoryId); 227 228 // Use the system property first 229 try { 230 String systemProp = ss.getSystemProperty(factoryId); 231 if (systemProp != null) { 232 dPrint("found system property, value=" + systemProp); 233 return newInstance(type, systemProp, null, true); 234 } 235 } 236 catch (SecurityException se) { 237 if (debug) se.printStackTrace(); 238 } 239 240 // try to read from $java.home/conf/jaxp.properties 241 try { 242 if (firstTime) { 243 synchronized (cacheProps) { 244 if (firstTime) { 245 String configFile = ss.getSystemProperty("java.home") + File.separator + 246 "conf" + File.separator + "jaxp.properties"; 247 File f = new File(configFile); 248 firstTime = false; 249 if (ss.doesFileExist(f)) { 250 dPrint("Read properties file "+f); 251 cacheProps.load(ss.getFileInputStream(f)); 252 } 253 } 254 } 255 } 256 final String factoryClassName = cacheProps.getProperty(factoryId); 257 258 if (factoryClassName != null) { 259 dPrint("found in ${java.home}/conf/jaxp.properties, value=" + factoryClassName); 260 return newInstance(type, factoryClassName, null, true); 261 } 262 } 263 catch (Exception ex) { 264 if (debug) ex.printStackTrace(); 265 } 266 267 // Try Jar Service Provider Mechanism 268 final T provider = findServiceProvider(type); 269 if (provider != null) { 270 return provider; 271 } 272 if (fallbackClassName == null) { 273 throw new DatatypeConfigurationException( 274 "Provider for " + factoryId + " cannot be found"); 275 } 276 277 dPrint("loaded from fallback value: " + fallbackClassName); 278 return newInstance(type, fallbackClassName, null, true); 279 } 280 281 /* 282 * Try to find provider using the ServiceLoader API 283 * 284 * @param type Base class / Service interface of the factory to find. 285 * 286 * @return instance of provider class if found or null 287 */ 288 private static <T> T findServiceProvider(final Class<T> type) 289 throws DatatypeConfigurationException 290 { 291 try { 292 return AccessController.doPrivileged(new PrivilegedAction<T>() { 293 public T run() { 294 final ServiceLoader<T> serviceLoader = ServiceLoader.load(type); 295 final Iterator<T> iterator = serviceLoader.iterator(); 296 if (iterator.hasNext()) { 297 return iterator.next(); 298 } else { 299 return null; 300 } 301 } 302 }); 303 } catch(ServiceConfigurationError e) { 304 final DatatypeConfigurationException error = 305 new DatatypeConfigurationException( 306 "Provider for " + type + " cannot be found", e); 307 throw error; 308 } 309 } 310 311 }