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.xpath;
27
28 import java.io.File;
29 import java.lang.reflect.Method;
30 import java.lang.reflect.Modifier;
31 import java.security.AccessControlContext;
32 import java.security.AccessController;
33 import java.security.PrivilegedAction;
34 import java.util.Properties;
35 import java.util.ServiceConfigurationError;
36 import java.util.ServiceLoader;
37
38 /**
39 * Implementation of {@link XPathFactory#newInstance(String)}.
40 *
41 * @author <a href="Kohsuke.Kawaguchi@Sun.com">Kohsuke Kawaguchi</a>
42 * @since 1.5
43 */
44 class XPathFactoryFinder {
45 private static final String DEFAULT_PACKAGE = "com.sun.org.apache.xpath.internal";
46
47 private static final SecuritySupport ss = new SecuritySupport() ;
48 /** debug support code. */
49 private static boolean debug = false;
50 static {
51 // Use try/catch block to support applets
52 try {
53 debug = ss.getSystemProperty("jaxp.debug") != null;
54 } catch (Exception unused) {
55 debug = false;
56 }
57 }
58
59 /**
60 * <p>Cache properties for performance.</p>
61 */
62 private static final Properties cacheProps = new Properties();
63
64 /**
65 * <p>First time requires initialization overhead.</p>
66 */
67 private volatile static boolean firstTime = true;
68
69 /**
70 * <p>Conditional debug printing.</p>
71 *
72 * @param msg to print
73 */
74 private static void debugPrintln(String msg) {
75 if (debug) {
76 System.err.println("JAXP: " + msg);
77 }
78 }
79
80 /**
81 * <p><code>ClassLoader</code> to use to find <code>XPathFactory</code>.</p>
82 */
83 private final ClassLoader classLoader;
84
85 /**
86 * <p>Constructor that specifies <code>ClassLoader</code> to use
87 * to find <code>XPathFactory</code>.</p>
88 *
89 * @param loader
90 * to be used to load resource and {@link XPathFactory}
91 * implementations during the resolution process.
92 * If this parameter is null, the default system class loader
93 * will be used.
94 */
95 public XPathFactoryFinder(ClassLoader loader) {
96 this.classLoader = loader;
97 if( debug ) {
98 debugDisplayClassLoader();
99 }
100 }
101
102 private void debugDisplayClassLoader() {
103 try {
104 if( classLoader == ss.getContextClassLoader() ) {
105 debugPrintln("using thread context class loader ("+classLoader+") for search");
106 return;
107 }
108 } catch( Throwable unused ) {
109 // getContextClassLoader() undefined in JDK1.1
110 }
111
112 if( classLoader==ClassLoader.getSystemClassLoader() ) {
113 debugPrintln("using system class loader ("+classLoader+") for search");
114 return;
115 }
116
117 debugPrintln("using class loader ("+classLoader+") for search");
118 }
119
120 /**
121 * <p>Creates a new {@link XPathFactory} object for the specified
122 * object model.</p>
123 *
124 * @param uri
125 * Identifies the underlying object model.
126 *
127 * @return <code>null</code> if the callee fails to create one.
128 *
129 * @throws NullPointerException
130 * If the parameter is null.
131 */
132 public XPathFactory newFactory(String uri) throws XPathFactoryConfigurationException {
133 if (uri == null) {
134 throw new NullPointerException();
135 }
136 XPathFactory f = _newFactory(uri);
137 if (f != null) {
138 debugPrintln("factory '" + f.getClass().getName() + "' was found for " + uri);
139 } else {
140 debugPrintln("unable to find a factory for " + uri);
141 }
142 return f;
143 }
144
145 /**
146 * <p>Lookup a {@link XPathFactory} for the given object model.</p>
147 *
148 * @param uri identifies the object model.
149 *
150 * @return {@link XPathFactory} for the given object model.
151 */
152 private XPathFactory _newFactory(String uri) throws XPathFactoryConfigurationException {
153 XPathFactory xpathFactory = null;
154
155 String propertyName = SERVICE_CLASS.getName() + ":" + uri;
156
157 // system property look up
158 try {
159 debugPrintln("Looking up system property '"+propertyName+"'" );
160 String r = ss.getSystemProperty(propertyName);
161 if(r!=null) {
162 debugPrintln("The value is '"+r+"'");
163 xpathFactory = createInstance(r, true);
164 if (xpathFactory != null) {
165 return xpathFactory;
166 }
167 } else
168 debugPrintln("The property is undefined.");
169 } catch( Throwable t ) {
170 if( debug ) {
171 debugPrintln("failed to look up system property '"+propertyName+"'" );
172 t.printStackTrace();
173 }
174 }
175
176 String javah = ss.getSystemProperty( "java.home" );
177 String configFile = javah + File.separator +
178 "lib" + File.separator + "jaxp.properties";
179
180 // try to read from $java.home/lib/jaxp.properties
181 try {
182 if(firstTime){
183 synchronized(cacheProps){
184 if(firstTime){
185 File f=new File( configFile );
186 firstTime = false;
187 if(ss.doesFileExist(f)){
188 debugPrintln("Read properties file " + f);
189 cacheProps.load(ss.getFileInputStream(f));
190 }
191 }
192 }
193 }
194 final String factoryClassName = cacheProps.getProperty(propertyName);
195 debugPrintln("found " + factoryClassName + " in $java.home/jaxp.properties");
196
197 if (factoryClassName != null) {
198 xpathFactory = createInstance(factoryClassName, true);
199 if(xpathFactory != null){
200 return xpathFactory;
201 }
202 }
203 } catch (Exception ex) {
204 if (debug) {
205 ex.printStackTrace();
206 }
207 }
208
209 // Try with ServiceLoader
210 assert xpathFactory == null;
211 xpathFactory = findServiceProvider(uri);
212
213 // The following assertion should always be true.
214 // Uncomment it, recompile, and run with -ea in case of doubts:
215 // assert xpathFactory == null || xpathFactory.isObjectModelSupported(uri);
216
217 if (xpathFactory != null) {
218 return xpathFactory;
219 }
220
221 // platform default
222 if(uri.equals(XPathFactory.DEFAULT_OBJECT_MODEL_URI)) {
223 debugPrintln("attempting to use the platform default W3C DOM XPath lib");
224 return createInstance("com.sun.org.apache.xpath.internal.jaxp.XPathFactoryImpl", true);
225 }
226
227 debugPrintln("all things were tried, but none was found. bailing out.");
228 return null;
229 }
230
231 /** <p>Create class using appropriate ClassLoader.</p>
232 *
233 * @param className Name of class to create.
234 * @return Created class or <code>null</code>.
235 */
236 private Class<?> createClass(String className) {
237 Class clazz;
238 // make sure we have access to restricted packages
239 boolean internal = false;
240 if (System.getSecurityManager() != null) {
241 if (className != null && className.startsWith(DEFAULT_PACKAGE)) {
242 internal = true;
243 }
244 }
245
246 // use approprite ClassLoader
247 try {
263 /**
264 * <p>Creates an instance of the specified and returns it.</p>
265 *
266 * @param className
267 * fully qualified class name to be instantiated.
268 *
269 * @return null
270 * if it fails. Error messages will be printed by this method.
271 */
272 XPathFactory createInstance( String className )
273 throws XPathFactoryConfigurationException
274 {
275 return createInstance( className, false );
276 }
277
278 XPathFactory createInstance( String className, boolean useServicesMechanism )
279 throws XPathFactoryConfigurationException
280 {
281 XPathFactory xPathFactory = null;
282
283 debugPrintln("createInstance(" + className + ")");
284
285 // get Class from className
286 Class<?> clazz = createClass(className);
287 if (clazz == null) {
288 debugPrintln("failed to getClass(" + className + ")");
289 return null;
290 }
291 debugPrintln("loaded " + className + " from " + which(clazz));
292
293 // instantiate Class as a XPathFactory
294 try {
295 if (!useServicesMechanism) {
296 xPathFactory = newInstanceNoServiceLoader(clazz);
297 }
298 if (xPathFactory == null) {
299 xPathFactory = (XPathFactory) clazz.newInstance();
300 }
301 } catch (ClassCastException classCastException) {
302 debugPrintln("could not instantiate " + clazz.getName());
303 if (debug) {
304 classCastException.printStackTrace();
305 }
306 return null;
307 } catch (IllegalAccessException illegalAccessException) {
308 debugPrintln("could not instantiate " + clazz.getName());
309 if (debug) {
310 illegalAccessException.printStackTrace();
311 }
312 return null;
313 } catch (InstantiationException instantiationException) {
314 debugPrintln("could not instantiate " + clazz.getName());
315 if (debug) {
316 instantiationException.printStackTrace();
317 }
318 return null;
319 }
320
321 return xPathFactory;
322 }
323 /**
324 * Try to construct using newXPathFactoryNoServiceLoader
325 * method if available.
326 */
327 private static XPathFactory newInstanceNoServiceLoader(
328 Class<?> providerClass
329 ) throws XPathFactoryConfigurationException {
330 // Retain maximum compatibility if no security manager.
331 if (System.getSecurityManager() == null) {
332 return null;
333 }
334 try {
|
1 /*
2 * Copyright (c) 2004, 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.xpath;
27
28 import java.io.File;
29 import java.lang.reflect.Method;
30 import java.lang.reflect.Modifier;
31 import java.security.AccessControlContext;
32 import java.security.AccessController;
33 import java.security.PrivilegedAction;
34 import java.util.Properties;
35 import java.util.ServiceConfigurationError;
36 import java.util.ServiceLoader;
37 import java.util.function.Supplier;
38
39 /**
40 * Implementation of {@link XPathFactory#newInstance(String)}.
41 *
42 * @author <a href="Kohsuke.Kawaguchi@Sun.com">Kohsuke Kawaguchi</a>
43 * @since 1.5
44 */
45 class XPathFactoryFinder {
46 private static final String DEFAULT_PACKAGE = "com.sun.org.apache.xpath.internal";
47
48 private static final SecuritySupport ss = new SecuritySupport() ;
49 /** debug support code. */
50 private static boolean debug = false;
51 static {
52 // Use try/catch block to support applets
53 try {
54 debug = ss.getSystemProperty("jaxp.debug") != null;
55 } catch (Exception unused) {
56 debug = false;
57 }
58 }
59
60 /**
61 * <p>Cache properties for performance.</p>
62 */
63 private static final Properties cacheProps = new Properties();
64
65 /**
66 * <p>First time requires initialization overhead.</p>
67 */
68 private volatile static boolean firstTime = true;
69
70 /**
71 * <p>Conditional debug printing.</p>
72 *
73 * @param msgGen Supplier function that returns debug message
74 */
75 private static void debugPrintln(Supplier<String> msgGen) {
76 if (debug) {
77 System.err.println("JAXP: " + msgGen.get());
78 }
79 }
80
81 /**
82 * <p><code>ClassLoader</code> to use to find <code>XPathFactory</code>.</p>
83 */
84 private final ClassLoader classLoader;
85
86 /**
87 * <p>Constructor that specifies <code>ClassLoader</code> to use
88 * to find <code>XPathFactory</code>.</p>
89 *
90 * @param loader
91 * to be used to load resource and {@link XPathFactory}
92 * implementations during the resolution process.
93 * If this parameter is null, the default system class loader
94 * will be used.
95 */
96 public XPathFactoryFinder(ClassLoader loader) {
97 this.classLoader = loader;
98 if( debug ) {
99 debugDisplayClassLoader();
100 }
101 }
102
103 private void debugDisplayClassLoader() {
104 try {
105 if( classLoader == ss.getContextClassLoader() ) {
106 debugPrintln(() -> "using thread context class loader ("+classLoader+") for search");
107 return;
108 }
109 } catch( Throwable unused ) {
110 // getContextClassLoader() undefined in JDK1.1
111 }
112
113 if( classLoader==ClassLoader.getSystemClassLoader() ) {
114 debugPrintln(() -> "using system class loader ("+classLoader+") for search");
115 return;
116 }
117
118 debugPrintln(() -> "using class loader ("+classLoader+") for search");
119 }
120
121 /**
122 * <p>Creates a new {@link XPathFactory} object for the specified
123 * object model.</p>
124 *
125 * @param uri
126 * Identifies the underlying object model.
127 *
128 * @return <code>null</code> if the callee fails to create one.
129 *
130 * @throws NullPointerException
131 * If the parameter is null.
132 */
133 public XPathFactory newFactory(String uri) throws XPathFactoryConfigurationException {
134 if (uri == null) {
135 throw new NullPointerException();
136 }
137 XPathFactory f = _newFactory(uri);
138 if (f != null) {
139 debugPrintln(()->"factory '" + f.getClass().getName() + "' was found for " + uri);
140 } else {
141 debugPrintln(()->"unable to find a factory for " + uri);
142 }
143 return f;
144 }
145
146 /**
147 * <p>Lookup a {@link XPathFactory} for the given object model.</p>
148 *
149 * @param uri identifies the object model.
150 *
151 * @return {@link XPathFactory} for the given object model.
152 */
153 private XPathFactory _newFactory(String uri) throws XPathFactoryConfigurationException {
154 XPathFactory xpathFactory = null;
155
156 String propertyName = SERVICE_CLASS.getName() + ":" + uri;
157
158 // system property look up
159 try {
160 debugPrintln(()->"Looking up system property '"+propertyName+"'" );
161 String r = ss.getSystemProperty(propertyName);
162 if(r!=null) {
163 debugPrintln(()->"The value is '"+r+"'");
164 xpathFactory = createInstance(r, true);
165 if (xpathFactory != null) {
166 return xpathFactory;
167 }
168 } else
169 debugPrintln(()->"The property is undefined.");
170 } catch( Throwable t ) {
171 if( debug ) {
172 debugPrintln(()->"failed to look up system property '"+propertyName+"'" );
173 t.printStackTrace();
174 }
175 }
176
177 String javah = ss.getSystemProperty( "java.home" );
178 String configFile = javah + File.separator +
179 "lib" + File.separator + "jaxp.properties";
180
181 // try to read from $java.home/lib/jaxp.properties
182 try {
183 if(firstTime){
184 synchronized(cacheProps){
185 if(firstTime){
186 File f=new File( configFile );
187 firstTime = false;
188 if(ss.doesFileExist(f)){
189 debugPrintln(()->"Read properties file " + f);
190 cacheProps.load(ss.getFileInputStream(f));
191 }
192 }
193 }
194 }
195 final String factoryClassName = cacheProps.getProperty(propertyName);
196 debugPrintln(()->"found " + factoryClassName + " in $java.home/jaxp.properties");
197
198 if (factoryClassName != null) {
199 xpathFactory = createInstance(factoryClassName, true);
200 if(xpathFactory != null){
201 return xpathFactory;
202 }
203 }
204 } catch (Exception ex) {
205 if (debug) {
206 ex.printStackTrace();
207 }
208 }
209
210 // Try with ServiceLoader
211 assert xpathFactory == null;
212 xpathFactory = findServiceProvider(uri);
213
214 // The following assertion should always be true.
215 // Uncomment it, recompile, and run with -ea in case of doubts:
216 // assert xpathFactory == null || xpathFactory.isObjectModelSupported(uri);
217
218 if (xpathFactory != null) {
219 return xpathFactory;
220 }
221
222 // platform default
223 if(uri.equals(XPathFactory.DEFAULT_OBJECT_MODEL_URI)) {
224 debugPrintln(()->"attempting to use the platform default W3C DOM XPath lib");
225 return createInstance("com.sun.org.apache.xpath.internal.jaxp.XPathFactoryImpl", true);
226 }
227
228 debugPrintln(()->"all things were tried, but none was found. bailing out.");
229 return null;
230 }
231
232 /** <p>Create class using appropriate ClassLoader.</p>
233 *
234 * @param className Name of class to create.
235 * @return Created class or <code>null</code>.
236 */
237 private Class<?> createClass(String className) {
238 Class clazz;
239 // make sure we have access to restricted packages
240 boolean internal = false;
241 if (System.getSecurityManager() != null) {
242 if (className != null && className.startsWith(DEFAULT_PACKAGE)) {
243 internal = true;
244 }
245 }
246
247 // use approprite ClassLoader
248 try {
264 /**
265 * <p>Creates an instance of the specified and returns it.</p>
266 *
267 * @param className
268 * fully qualified class name to be instantiated.
269 *
270 * @return null
271 * if it fails. Error messages will be printed by this method.
272 */
273 XPathFactory createInstance( String className )
274 throws XPathFactoryConfigurationException
275 {
276 return createInstance( className, false );
277 }
278
279 XPathFactory createInstance( String className, boolean useServicesMechanism )
280 throws XPathFactoryConfigurationException
281 {
282 XPathFactory xPathFactory = null;
283
284 debugPrintln(()->"createInstance(" + className + ")");
285
286 // get Class from className
287 Class<?> clazz = createClass(className);
288 if (clazz == null) {
289 debugPrintln(()->"failed to getClass(" + className + ")");
290 return null;
291 }
292 debugPrintln(()->"loaded " + className + " from " + which(clazz));
293
294 // instantiate Class as a XPathFactory
295 try {
296 if (!useServicesMechanism) {
297 xPathFactory = newInstanceNoServiceLoader(clazz);
298 }
299 if (xPathFactory == null) {
300 xPathFactory = (XPathFactory) clazz.newInstance();
301 }
302 } catch (ClassCastException classCastException) {
303 debugPrintln(()->"could not instantiate " + clazz.getName());
304 if (debug) {
305 classCastException.printStackTrace();
306 }
307 return null;
308 } catch (IllegalAccessException illegalAccessException) {
309 debugPrintln(()->"could not instantiate " + clazz.getName());
310 if (debug) {
311 illegalAccessException.printStackTrace();
312 }
313 return null;
314 } catch (InstantiationException instantiationException) {
315 debugPrintln(()->"could not instantiate " + clazz.getName());
316 if (debug) {
317 instantiationException.printStackTrace();
318 }
319 return null;
320 }
321
322 return xPathFactory;
323 }
324 /**
325 * Try to construct using newXPathFactoryNoServiceLoader
326 * method if available.
327 */
328 private static XPathFactory newInstanceNoServiceLoader(
329 Class<?> providerClass
330 ) throws XPathFactoryConfigurationException {
331 // Retain maximum compatibility if no security manager.
332 if (System.getSecurityManager() == null) {
333 return null;
334 }
335 try {
|