1 /*
2 * Copyright (c) 2004, 2017, 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 import java.util.function.Supplier;
36 import jdk.xml.internal.SecuritySupport;
37
38 /**
39 * <p>Implements pluggable Datatypes.</p>
40 *
41 * <p>This class is duplicated for each JAXP subpackage so keep it in
42 * sync. It is package private for secure class loading.</p>
43 *
44 * @author Santiago.PericasGeertsen@sun.com
45 */
46 class FactoryFinder {
47 private static final String DEFAULT_PACKAGE = "com.sun.org.apache.xerces.internal";
48
49 /**
50 * Internal debug flag.
51 */
52 private static boolean debug = false;
53
54 /**
55 * Cache for properties in java.home/conf/jaxp.properties
56 */
57 private final static Properties cacheProps = new Properties();
58
59 /**
60 * Flag indicating if properties from java.home/conf/jaxp.properties
61 * have been cached.
62 */
63 private static volatile boolean firstTime = true;
64
65 // Define system property "jaxp.debug" to get output
66 static {
67 // Use try/catch block to support applets, which throws
68 // SecurityException out of this code.
69 try {
70 String val = SecuritySupport.getSystemProperty("jaxp.debug");
71 // Allow simply setting the prop to turn on debug
72 debug = val != null && !"false".equals(val);
73 }
74 catch (SecurityException se) {
75 debug = false;
76 }
77 }
78
79 private static void dPrint(Supplier<String> msgGen) {
80 if (debug) {
81 System.err.println("JAXP: " + msgGen.get());
82 }
83 }
84
85 /**
86 * Attempt to load a class using the class loader supplied. If that fails
87 * and fall back is enabled, the current (i.e. bootstrap) class loader is
88 * tried.
89 *
90 * If the class loader supplied is <code>null</code>, first try using the
91 * context class loader followed by the current (i.e. bootstrap) class
92 * loader.
93 *
94 * Use bootstrap classLoader if cl = null and useBSClsLoader is true
95 */
96 static private Class<?> getProviderClass(String className, ClassLoader cl,
97 boolean doFallback, boolean useBSClsLoader) throws ClassNotFoundException
98 {
99 try {
100 if (cl == null) {
101 if (useBSClsLoader) {
102 return Class.forName(className, false, FactoryFinder.class.getClassLoader());
103 } else {
104 cl = SecuritySupport.getContextClassLoader();
105 if (cl == null) {
106 throw new ClassNotFoundException();
107 }
108 else {
109 return Class.forName(className, false, cl);
110 }
111 }
112 }
113 else {
114 return Class.forName(className, false, cl);
115 }
116 }
117 catch (ClassNotFoundException e1) {
118 if (doFallback) {
119 // Use current class loader - should always be bootstrap CL
120 return Class.forName(className, false, FactoryFinder.class.getClassLoader());
121 }
122 else {
123 throw e1;
124 }
125 }
126 }
127
128 /**
129 * Create an instance of a class. Delegates to method
130 * <code>getProviderClass()</code> in order to load the class.
131 *
132 * @param type Base class / Service interface of the factory to
133 * instantiate.
134 *
135 * @param className Name of the concrete class corresponding to the
136 * service provider
137 *
138 * @param cl <code>ClassLoader</code> used to load the factory class. If <code>null</code>
139 * current <code>Thread</code>'s context classLoader is used to load the factory class.
140 *
141 * @param doFallback True if the current ClassLoader should be tried as
142 * a fallback if the class is not found using cl
143 */
144 static <T> T newInstance(Class<T> type, String className, ClassLoader cl, boolean doFallback)
145 throws DatatypeConfigurationException
146 {
147 return newInstance(type, className, cl, doFallback, false);
148 }
149
150 /**
151 * Create an instance of a class. Delegates to method
152 * <code>getProviderClass()</code> in order to load the class.
153 *
154 * @param type Base class / Service interface of the factory to
155 * instantiate.
156 *
157 * @param className Name of the concrete class corresponding to the
158 * service provider
159 *
160 * @param cl ClassLoader to use to load the class, null means to use
161 * the bootstrap ClassLoader
162 *
163 * @param doFallback True if the current ClassLoader should be tried as
164 * a fallback if the class is not found using cl
165 *
166 * @param useBSClsLoader True if cl=null actually meant bootstrap classLoader. This parameter
167 * is needed since DocumentBuilderFactory/SAXParserFactory defined null as context classLoader.
168 */
169 static <T> T newInstance(Class<T> type, String className, ClassLoader cl,
170 boolean doFallback, boolean useBSClsLoader)
171 throws DatatypeConfigurationException
172 {
173 assert type != null;
174
175 // make sure we have access to restricted packages
176 if (System.getSecurityManager() != null) {
177 if (className != null && className.startsWith(DEFAULT_PACKAGE)) {
178 cl = null;
179 useBSClsLoader = true;
180 }
181 }
182
183 try {
184 Class<?> providerClass = getProviderClass(className, cl, doFallback, useBSClsLoader);
185 if (!type.isAssignableFrom(providerClass)) {
186 throw new ClassCastException(className + " cannot be cast to " + type.getName());
187 }
188 Object instance = providerClass.getConstructor().newInstance();
189 final ClassLoader clD = cl;
190 dPrint(()->"created new instance of " + providerClass +
191 " using ClassLoader: " + clD);
192 return type.cast(instance);
193 }
194 catch (ClassNotFoundException x) {
195 throw new DatatypeConfigurationException(
196 "Provider " + className + " not found", x);
197 }
198 catch (Exception x) {
199 throw new DatatypeConfigurationException(
200 "Provider " + className + " could not be instantiated: " + x,
201 x);
202 }
203 }
204
205 /**
206 * Finds the implementation Class object in the specified order. Main
207 * entry point.
208 * @return Class object of factory, never null
209 *
210 * @param type Base class / Service interface of the
211 * factory to find.
212 * @param fallbackClassName Implementation class name, if nothing else
213 * is found. Use null to mean no fallback.
214 *
215 * Package private so this code can be shared.
216 */
217 static <T> T find(Class<T> type, String fallbackClassName)
218 throws DatatypeConfigurationException
219 {
220 final String factoryId = type.getName();
221 dPrint(()->"find factoryId =" + factoryId);
222
223 // Use the system property first
224 try {
225 String systemProp = SecuritySupport.getSystemProperty(factoryId);
226 if (systemProp != null) {
227 dPrint(()->"found system property, value=" + systemProp);
228 return newInstance(type, systemProp, null, true);
229 }
230 }
231 catch (SecurityException se) {
232 if (debug) se.printStackTrace();
233 }
234
235 // try to read from $java.home/conf/jaxp.properties
236 try {
237 if (firstTime) {
238 synchronized (cacheProps) {
239 if (firstTime) {
240 String configFile = SecuritySupport.getSystemProperty("java.home") + File.separator +
241 "conf" + File.separator + "jaxp.properties";
242 File f = new File(configFile);
243 firstTime = false;
244 if (SecuritySupport.doesFileExist(f)) {
245 dPrint(()->"Read properties file "+f);
246 cacheProps.load(SecuritySupport.getFileInputStream(f));
247 }
248 }
249 }
250 }
251 final String factoryClassName = cacheProps.getProperty(factoryId);
252
253 if (factoryClassName != null) {
254 dPrint(()->"found in ${java.home}/conf/jaxp.properties, value=" + factoryClassName);
255 return newInstance(type, factoryClassName, null, true);
256 }
257 }
258 catch (Exception ex) {
259 if (debug) ex.printStackTrace();
260 }
261
262 // Try Jar Service Provider Mechanism
263 final T provider = findServiceProvider(type);
264 if (provider != null) {
265 return provider;
266 }
267 if (fallbackClassName == null) {
268 throw new DatatypeConfigurationException(
269 "Provider for " + factoryId + " cannot be found");
270 }
271
272 dPrint(()->"loaded from fallback value: " + fallbackClassName);
273 return newInstance(type, fallbackClassName, null, true);
274 }
275
276 /*
277 * Try to find provider using the ServiceLoader API
278 *
279 * @param type Base class / Service interface of the factory to find.
280 *
281 * @return instance of provider class if found or null
282 */
283 private static <T> T findServiceProvider(final Class<T> type)
284 throws DatatypeConfigurationException
285 {
286 try {
287 return AccessController.doPrivileged(new PrivilegedAction<T>() {
288 public T run() {
289 final ServiceLoader<T> serviceLoader = ServiceLoader.load(type);
290 final Iterator<T> iterator = serviceLoader.iterator();
291 if (iterator.hasNext()) {
292 return iterator.next();
293 } else {
294 return null;
295 }
296 }
297 });
298 } catch(ServiceConfigurationError e) {
299 final DatatypeConfigurationException error =
300 new DatatypeConfigurationException(
301 "Provider for " + type + " cannot be found", e);
302 throw error;
303 }
304 }
305
306 }