1 /* 2 * Copyright (c) 2001, 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 sun.reflect; 27 28 import java.lang.reflect.Field; 29 import java.lang.reflect.Executable; 30 import java.lang.reflect.Method; 31 import java.lang.reflect.Constructor; 32 import java.lang.reflect.Modifier; 33 import java.security.AccessController; 34 import java.security.Permission; 35 import java.security.PrivilegedAction; 36 import sun.reflect.misc.ReflectUtil; 37 38 /** <P> The master factory for all reflective objects, both those in 39 java.lang.reflect (Fields, Methods, Constructors) as well as their 40 delegates (FieldAccessors, MethodAccessors, ConstructorAccessors). 41 </P> 42 43 <P> The methods in this class are extremely unsafe and can cause 44 subversion of both the language and the verifier. For this reason, 45 they are all instance methods, and access to the constructor of 46 this factory is guarded by a security check, in similar style to 47 {@link sun.misc.Unsafe}. </P> 48 */ 49 50 public class ReflectionFactory { 51 52 private static boolean initted = false; 53 private static final Permission reflectionFactoryAccessPerm 54 = new RuntimePermission("reflectionFactoryAccess"); 55 private static final ReflectionFactory soleInstance = new ReflectionFactory(); 56 // Provides access to package-private mechanisms in java.lang.reflect 57 private static volatile LangReflectAccess langReflectAccess; 58 59 // 60 // "Inflation" mechanism. Loading bytecodes to implement 61 // Method.invoke() and Constructor.newInstance() currently costs 62 // 3-4x more than an invocation via native code for the first 63 // invocation (though subsequent invocations have been benchmarked 64 // to be over 20x faster). Unfortunately this cost increases 65 // startup time for certain applications that use reflection 66 // intensively (but only once per class) to bootstrap themselves. 67 // To avoid this penalty we reuse the existing JVM entry points 68 // for the first few invocations of Methods and Constructors and 69 // then switch to the bytecode-based implementations. 70 // 71 // Package-private to be accessible to NativeMethodAccessorImpl 72 // and NativeConstructorAccessorImpl 73 private static boolean noInflation = false; 74 private static int inflationThreshold = 15; 75 76 private ReflectionFactory() { 77 } 78 79 /** 80 * A convenience class for acquiring the capability to instantiate 81 * reflective objects. Use this instead of a raw call to {@link 82 * #getReflectionFactory} in order to avoid being limited by the 83 * permissions of your callers. 84 * 85 * <p>An instance of this class can be used as the argument of 86 * <code>AccessController.doPrivileged</code>. 87 */ 88 public static final class GetReflectionFactoryAction 89 implements PrivilegedAction<ReflectionFactory> { 90 public ReflectionFactory run() { 91 return getReflectionFactory(); 92 } 93 } 94 95 /** 96 * Provides the caller with the capability to instantiate reflective 97 * objects. 98 * 99 * <p> First, if there is a security manager, its 100 * <code>checkPermission</code> method is called with a {@link 101 * java.lang.RuntimePermission} with target 102 * <code>"reflectionFactoryAccess"</code>. This may result in a 103 * security exception. 104 * 105 * <p> The returned <code>ReflectionFactory</code> object should be 106 * carefully guarded by the caller, since it can be used to read and 107 * write private data and invoke private methods, as well as to load 108 * unverified bytecodes. It must never be passed to untrusted code. 109 * 110 * @exception SecurityException if a security manager exists and its 111 * <code>checkPermission</code> method doesn't allow 112 * access to the RuntimePermission "reflectionFactoryAccess". */ 113 public static ReflectionFactory getReflectionFactory() { 114 SecurityManager security = System.getSecurityManager(); 115 if (security != null) { 116 // TO DO: security.checkReflectionFactoryAccess(); 117 security.checkPermission(reflectionFactoryAccessPerm); 118 } 119 return soleInstance; 120 } 121 122 //-------------------------------------------------------------------------- 123 // 124 // Routines used by java.lang.reflect 125 // 126 // 127 128 /** Called only by java.lang.reflect.Modifier's static initializer */ 129 public void setLangReflectAccess(LangReflectAccess access) { 130 langReflectAccess = access; 131 } 132 133 /** 134 * Note: this routine can cause the declaring class for the field 135 * be initialized and therefore must not be called until the 136 * first get/set of this field. 137 * @param field the field 138 * @param override true if caller has overridden accessibility 139 */ 140 public FieldAccessor newFieldAccessor(Field field, boolean override) { 141 checkInitted(); 142 return UnsafeFieldAccessorFactory.newFieldAccessor(field, override); 143 } 144 145 public MethodAccessor newMethodAccessor(Method method) { 146 checkInitted(); 147 148 if (noInflation && !ReflectUtil.isVMAnonymousClass(method.getDeclaringClass())) { 149 return new MethodAccessorGenerator(). 150 generateMethod(method.getDeclaringClass(), 151 method.getName(), 152 method.getParameterTypes(), 153 method.getReturnType(), 154 method.getExceptionTypes(), 155 method.getModifiers()); 156 } else { 157 NativeMethodAccessorImpl acc = 158 new NativeMethodAccessorImpl(method); 159 DelegatingMethodAccessorImpl res = 160 new DelegatingMethodAccessorImpl(acc); 161 acc.setParent(res); 162 return res; 163 } 164 } 165 166 public ConstructorAccessor newConstructorAccessor(Constructor<?> c) { 167 checkInitted(); 168 169 Class<?> declaringClass = c.getDeclaringClass(); 170 if (Modifier.isAbstract(declaringClass.getModifiers())) { 171 return new InstantiationExceptionConstructorAccessorImpl(null); 172 } 173 if (declaringClass == Class.class) { 174 return new InstantiationExceptionConstructorAccessorImpl 175 ("Can not instantiate java.lang.Class"); 176 } 177 // Bootstrapping issue: since we use Class.newInstance() in 178 // the ConstructorAccessor generation process, we have to 179 // break the cycle here. 180 if (Reflection.isSubclassOf(declaringClass, 181 ConstructorAccessorImpl.class)) { 182 return new BootstrapConstructorAccessorImpl(c); 183 } 184 185 if (noInflation && !ReflectUtil.isVMAnonymousClass(c.getDeclaringClass())) { 186 return new MethodAccessorGenerator(). 187 generateConstructor(c.getDeclaringClass(), 188 c.getParameterTypes(), 189 c.getExceptionTypes(), 190 c.getModifiers()); 191 } else { 192 NativeConstructorAccessorImpl acc = 193 new NativeConstructorAccessorImpl(c); 194 DelegatingConstructorAccessorImpl res = 195 new DelegatingConstructorAccessorImpl(acc); 196 acc.setParent(res); 197 return res; 198 } 199 } 200 201 //-------------------------------------------------------------------------- 202 // 203 // Routines used by java.lang 204 // 205 // 206 207 /** Creates a new java.lang.reflect.Field. Access checks as per 208 java.lang.reflect.AccessibleObject are not overridden. */ 209 public Field newField(Class<?> declaringClass, 210 String name, 211 Class<?> type, 212 int modifiers, 213 int slot, 214 String signature, 215 byte[] annotations) 216 { 217 return langReflectAccess().newField(declaringClass, 218 name, 219 type, 220 modifiers, 221 slot, 222 signature, 223 annotations); 224 } 225 226 /** Creates a new java.lang.reflect.Method. Access checks as per 227 java.lang.reflect.AccessibleObject are not overridden. */ 228 public Method newMethod(Class<?> declaringClass, 229 String name, 230 Class<?>[] parameterTypes, 231 Class<?> returnType, 232 Class<?>[] checkedExceptions, 233 int modifiers, 234 int slot, 235 String signature, 236 byte[] annotations, 237 byte[] parameterAnnotations, 238 byte[] annotationDefault) 239 { 240 return langReflectAccess().newMethod(declaringClass, 241 name, 242 parameterTypes, 243 returnType, 244 checkedExceptions, 245 modifiers, 246 slot, 247 signature, 248 annotations, 249 parameterAnnotations, 250 annotationDefault); 251 } 252 253 /** Creates a new java.lang.reflect.Constructor. Access checks as 254 per java.lang.reflect.AccessibleObject are not overridden. */ 255 public Constructor<?> newConstructor(Class<?> declaringClass, 256 Class<?>[] parameterTypes, 257 Class<?>[] checkedExceptions, 258 int modifiers, 259 int slot, 260 String signature, 261 byte[] annotations, 262 byte[] parameterAnnotations) 263 { 264 return langReflectAccess().newConstructor(declaringClass, 265 parameterTypes, 266 checkedExceptions, 267 modifiers, 268 slot, 269 signature, 270 annotations, 271 parameterAnnotations); 272 } 273 274 /** Gets the MethodAccessor object for a java.lang.reflect.Method */ 275 public MethodAccessor getMethodAccessor(Method m) { 276 return langReflectAccess().getMethodAccessor(m); 277 } 278 279 /** Sets the MethodAccessor object for a java.lang.reflect.Method */ 280 public void setMethodAccessor(Method m, MethodAccessor accessor) { 281 langReflectAccess().setMethodAccessor(m, accessor); 282 } 283 284 /** Gets the ConstructorAccessor object for a 285 java.lang.reflect.Constructor */ 286 public ConstructorAccessor getConstructorAccessor(Constructor<?> c) { 287 return langReflectAccess().getConstructorAccessor(c); 288 } 289 290 /** Sets the ConstructorAccessor object for a 291 java.lang.reflect.Constructor */ 292 public void setConstructorAccessor(Constructor<?> c, 293 ConstructorAccessor accessor) 294 { 295 langReflectAccess().setConstructorAccessor(c, accessor); 296 } 297 298 /** Makes a copy of the passed method. The returned method is a 299 "child" of the passed one; see the comments in Method.java for 300 details. */ 301 public Method copyMethod(Method arg) { 302 return langReflectAccess().copyMethod(arg); 303 } 304 305 /** Makes a copy of the passed field. The returned field is a 306 "child" of the passed one; see the comments in Field.java for 307 details. */ 308 public Field copyField(Field arg) { 309 return langReflectAccess().copyField(arg); 310 } 311 312 /** Makes a copy of the passed constructor. The returned 313 constructor is a "child" of the passed one; see the comments 314 in Constructor.java for details. */ 315 public <T> Constructor<T> copyConstructor(Constructor<T> arg) { 316 return langReflectAccess().copyConstructor(arg); 317 } 318 319 /** Gets the byte[] that encodes TypeAnnotations on an executable. 320 */ 321 public byte[] getExecutableTypeAnnotationBytes(Executable ex) { 322 return langReflectAccess().getExecutableTypeAnnotationBytes(ex); 323 } 324 325 //-------------------------------------------------------------------------- 326 // 327 // Routines used by serialization 328 // 329 // 330 331 public Constructor<?> newConstructorForSerialization 332 (Class<?> classToInstantiate, Constructor<?> constructorToCall) 333 { 334 // Fast path 335 if (constructorToCall.getDeclaringClass() == classToInstantiate) { 336 return constructorToCall; 337 } 338 339 ConstructorAccessor acc = new MethodAccessorGenerator(). 340 generateSerializationConstructor(classToInstantiate, 341 constructorToCall.getParameterTypes(), 342 constructorToCall.getExceptionTypes(), 343 constructorToCall.getModifiers(), 344 constructorToCall.getDeclaringClass()); 345 Constructor<?> c = newConstructor(constructorToCall.getDeclaringClass(), 346 constructorToCall.getParameterTypes(), 347 constructorToCall.getExceptionTypes(), 348 constructorToCall.getModifiers(), 349 langReflectAccess(). 350 getConstructorSlot(constructorToCall), 351 langReflectAccess(). 352 getConstructorSignature(constructorToCall), 353 langReflectAccess(). 354 getConstructorAnnotations(constructorToCall), 355 langReflectAccess(). 356 getConstructorParameterAnnotations(constructorToCall)); 357 setConstructorAccessor(c, acc); 358 return c; 359 } 360 361 //-------------------------------------------------------------------------- 362 // 363 // Internals only below this point 364 // 365 366 static int inflationThreshold() { 367 return inflationThreshold; 368 } 369 370 /** We have to defer full initialization of this class until after 371 the static initializer is run since java.lang.reflect.Method's 372 static initializer (more properly, that for 373 java.lang.reflect.AccessibleObject) causes this class's to be 374 run, before the system properties are set up. */ 375 private static void checkInitted() { 376 if (initted) return; 377 AccessController.doPrivileged( 378 new PrivilegedAction<Void>() { 379 public Void run() { 380 // Tests to ensure the system properties table is fully 381 // initialized. This is needed because reflection code is 382 // called very early in the initialization process (before 383 // command-line arguments have been parsed and therefore 384 // these user-settable properties installed.) We assume that 385 // if System.out is non-null then the System class has been 386 // fully initialized and that the bulk of the startup code 387 // has been run. 388 389 if (System.out == null) { 390 // java.lang.System not yet fully initialized 391 return null; 392 } 393 394 String val = System.getProperty("sun.reflect.noInflation"); 395 if (val != null && val.equals("true")) { 396 noInflation = true; 397 } 398 399 val = System.getProperty("sun.reflect.inflationThreshold"); 400 if (val != null) { 401 try { 402 inflationThreshold = Integer.parseInt(val); 403 } catch (NumberFormatException e) { 404 throw new RuntimeException("Unable to parse property sun.reflect.inflationThreshold", e); 405 } 406 } 407 408 initted = true; 409 return null; 410 } 411 }); 412 } 413 414 private static LangReflectAccess langReflectAccess() { 415 if (langReflectAccess == null) { 416 // Call a static method to get class java.lang.reflect.Modifier 417 // initialized. Its static initializer will cause 418 // setLangReflectAccess() to be called from the context of the 419 // java.lang.reflect package. 420 Modifier.isPublic(Modifier.PUBLIC); 421 } 422 return langReflectAccess; 423 } 424 }