1 /*
2 * Copyright (c) 2003, 2016, 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.transform;
27
28 import java.io.File;
29 import java.lang.reflect.Method;
30 import java.lang.reflect.Modifier;
31 import java.security.AccessController;
32 import java.security.PrivilegedAction;
33 import java.util.Iterator;
34 import java.util.Properties;
35 import java.util.ServiceConfigurationError;
36 import java.util.ServiceLoader;
37 import java.util.function.Supplier;
38
39 /**
40 * <p>Implements pluggable Datatypes.</p>
41 *
42 * <p>This class is duplicated for each JAXP subpackage so keep it in
43 * sync. It is package private for secure class loading.</p>
44 *
45 * @author Santiago.PericasGeertsen@sun.com
46 * @author Huizhe.Wang@oracle.com
47 */
48 class FactoryFinder {
49 private static final String DEFAULT_PACKAGE = "com.sun.org.apache.xalan.internal.";
50
51 /**
52 * Internal debug flag.
53 */
54 private static boolean debug = false;
55
56 /**
57 * Cache for properties in java.home/conf/jaxp.properties
58 */
59 private final static Properties cacheProps = new Properties();
60
61 /**
62 * Flag indicating if properties from java.home/conf/jaxp.properties
63 * have been cached.
64 */
65 static volatile boolean firstTime = true;
66
67 /**
68 * Security support class use to check access control before
69 * getting certain system resources.
70 */
71 private final static SecuritySupport ss = new SecuritySupport();
72
73 // Define system property "jaxp.debug" to get output
74 static {
75 // Use try/catch block to support applets, which throws
76 // SecurityException out of this code.
77 try {
78 String val = ss.getSystemProperty("jaxp.debug");
79 // Allow simply setting the prop to turn on debug
80 debug = val != null && !"false".equals(val);
81 }
82 catch (SecurityException se) {
83 debug = false;
84 }
85 }
86
87 private static void dPrint(Supplier<String> msgGen) {
88 if (debug) {
89 System.err.println("JAXP: " + msgGen.get());
90 }
91 }
92
93 /**
94 * Attempt to load a class using the class loader supplied. If that fails
95 * and fall back is enabled, the current (i.e. bootstrap) class loader is
96 * tried.
97 *
98 * If the class loader supplied is <code>null</code>, first try using the
99 * context class loader followed by the current (i.e. bootstrap) class
100 * loader.
101 *
102 * Use bootstrap classLoader if cl = null and useBSClsLoader is true
103 */
104 static private Class<?> getProviderClass(String className, ClassLoader cl,
105 boolean doFallback, boolean useBSClsLoader) throws ClassNotFoundException
106 {
107 try {
108 if (cl == null) {
109 if (useBSClsLoader) {
110 return Class.forName(className, false, FactoryFinder.class.getClassLoader());
111 } else {
112 cl = ss.getContextClassLoader();
113 if (cl == null) {
114 throw new ClassNotFoundException();
115 }
116 else {
117 return Class.forName(className, false, cl);
118 }
119 }
120 }
121 else {
122 return Class.forName(className, false, cl);
123 }
124 }
125 catch (ClassNotFoundException e1) {
126 if (doFallback) {
127 // Use current class loader - should always be bootstrap CL
128 return Class.forName(className, false, FactoryFinder.class.getClassLoader());
129 }
130 else {
131 throw e1;
132 }
133 }
134 }
135
136 /**
137 * Create an instance of a class. Delegates to method
138 * <code>getProviderClass()</code> in order to load the class.
139 *
140 * @param type Base class / Service interface of the factory to
141 * instantiate.
142 *
143 * @param className Name of the concrete class corresponding to the
144 * service provider
145 *
146 * @param cl <code>ClassLoader</code> used to load the factory class. If <code>null</code>
147 * current <code>Thread</code>'s context classLoader is used to load the factory class.
148 *
149 * @param doFallback True if the current ClassLoader should be tried as
150 * a fallback if the class is not found using cl
151 *
152 * @param useServicesMechanism True use services mechanism
153 */
154 static <T> T newInstance(Class<T> type, String className, ClassLoader cl,
155 boolean doFallback, boolean useServicesMechanism)
156 throws TransformerFactoryConfigurationError
157 {
158 assert type != null;
159
160 boolean useBSClsLoader = false;
161 // make sure we have access to restricted packages
162 if (System.getSecurityManager() != null) {
163 if (className != null && className.startsWith(DEFAULT_PACKAGE)) {
164 cl = null;
165 useBSClsLoader = true;
166 }
167 }
168
169 try {
170 Class<?> providerClass = getProviderClass(className, cl, doFallback, useBSClsLoader);
171 if (!type.isAssignableFrom(providerClass)) {
172 throw new ClassCastException(className + " cannot be cast to " + type.getName());
173 }
174 Object instance = null;
175 if (!useServicesMechanism) {
176 instance = newInstanceNoServiceLoader(type, providerClass);
177 }
178 if (instance == null) {
179 instance = providerClass.newInstance();
180 }
181 final ClassLoader clD = cl;
182 dPrint(()->"created new instance of " + providerClass +
183 " using ClassLoader: " + clD);
184 return type.cast(instance);
185 }
186 catch (ClassNotFoundException x) {
187 throw new TransformerFactoryConfigurationError(x,
188 "Provider " + className + " not found");
189 }
190 catch (Exception x) {
191 throw new TransformerFactoryConfigurationError(x,
192 "Provider " + className + " could not be instantiated: " + x);
193 }
194 }
195
196 /**
197 * Try to construct using newTransformerFactoryNoServiceLoader
198 * method if available.
199 */
200 private static <T> T newInstanceNoServiceLoader(Class<T> type, Class<?> providerClass) {
201 // Retain maximum compatibility if no security manager.
202 if (System.getSecurityManager() == null) {
203 return null;
204 }
205 try {
206 final Method creationMethod =
207 providerClass.getDeclaredMethod(
208 "newTransformerFactoryNoServiceLoader"
209 );
210 final int modifiers = creationMethod.getModifiers();
211
212 // Do not call the method if it's not public static.
213 if (!Modifier.isPublic(modifiers) || !Modifier.isStatic(modifiers)) {
214 return null;
215 }
216
217 // Only call the method if it's declared to return an instance of
218 // TransformerFactory
219 final Class<?> returnType = creationMethod.getReturnType();
220 if (type.isAssignableFrom(returnType)) {
221 final Object result = creationMethod.invoke(null, (Object[])null);
222 return type.cast(result);
223 } else {
224 // This should not happen, as
225 // TransformerFactoryImpl.newTransformerFactoryNoServiceLoader is
226 // declared to return TransformerFactory.
227 throw new ClassCastException(returnType + " cannot be cast to " + type);
228 }
229 } catch (ClassCastException e) {
230 throw new TransformerFactoryConfigurationError(e, e.getMessage());
231 } catch (NoSuchMethodException exc) {
232 return null;
233 } catch (Exception exc) {
234 return null;
235 }
236 }
237
238 /**
239 * Finds the implementation Class object in the specified order. Main
240 * entry point.
241 * @return Class object of factory, never null
242 *
243 * @param type Base class / Service interface of the
244 * factory to find.
245 *
246 * @param fallbackClassName Implementation class name, if nothing else
247 * is found. Use null to mean no fallback.
248 *
249 * Package private so this code can be shared.
250 */
251 static <T> T find(Class<T> type, String fallbackClassName)
252 throws TransformerFactoryConfigurationError
253 {
254 assert type != null;
255
256 final String factoryId = type.getName();
257
258 dPrint(()->"find factoryId =" + factoryId);
259 // Use the system property first
260 try {
261 String systemProp = ss.getSystemProperty(factoryId);
262 if (systemProp != null) {
263 dPrint(()->"found system property, value=" + systemProp);
264 return newInstance(type, systemProp, null, true, true);
265 }
266 }
267 catch (SecurityException se) {
268 if (debug) se.printStackTrace();
269 }
270
271 // try to read from $java.home/conf/jaxp.properties
272 try {
273 if (firstTime) {
274 synchronized (cacheProps) {
275 if (firstTime) {
276 String configFile = ss.getSystemProperty("java.home") + File.separator +
277 "conf" + File.separator + "jaxp.properties";
278 File f = new File(configFile);
279 firstTime = false;
280 if (ss.doesFileExist(f)) {
281 dPrint(()->"Read properties file "+f);
282 cacheProps.load(ss.getFileInputStream(f));
283 }
284 }
285 }
286 }
287 final String factoryClassName = cacheProps.getProperty(factoryId);
288
289 if (factoryClassName != null) {
290 dPrint(()->"found in ${java.home}/conf/jaxp.properties, value=" + factoryClassName);
291 return newInstance(type, factoryClassName, null, true, true);
292 }
293 }
294 catch (Exception ex) {
295 if (debug) ex.printStackTrace();
296 }
297
298 // Try Jar Service Provider Mechanism
299 T provider = findServiceProvider(type);
300 if (provider != null) {
301 return provider;
302 }
303 if (fallbackClassName == null) {
304 throw new TransformerFactoryConfigurationError(null,
305 "Provider for " + factoryId + " cannot be found");
306 }
307
308 dPrint(()->"loaded from fallback value: " + fallbackClassName);
309 return newInstance(type, fallbackClassName, null, true, true);
310 }
311
312 /*
313 * Try to find provider using the ServiceLoader.
314 *
315 * @param type Base class / Service interface of the factory to find.
316 *
317 * @return instance of provider class if found or null
318 */
319 private static <T> T findServiceProvider(final Class<T> type)
320 throws TransformerFactoryConfigurationError
321 {
322 try {
323 return AccessController.doPrivileged(new PrivilegedAction<T>() {
324 public T run() {
325 final ServiceLoader<T> serviceLoader = ServiceLoader.load(type);
326 final Iterator<T> iterator = serviceLoader.iterator();
327 if (iterator.hasNext()) {
328 return iterator.next();
329 } else {
330 return null;
331 }
332 }
333 });
334 } catch(ServiceConfigurationError e) {
335 // It is not possible to wrap an error directly in
336 // FactoryConfigurationError - so we need to wrap the
337 // ServiceConfigurationError in a RuntimeException.
338 // The alternative would be to modify the logic in
339 // FactoryConfigurationError to allow setting a
340 // Throwable as the cause, but that could cause
341 // compatibility issues down the road.
342 final RuntimeException x = new RuntimeException(
343 "Provider for " + type + " cannot be created", e);
344 final TransformerFactoryConfigurationError error =
345 new TransformerFactoryConfigurationError(x, x.getMessage());
346 throw error;
347 }
348 }
349 }