J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1999-2006 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package javax.management; |
| 27 | |
| 28 | import java.io.IOException; |
| 29 | import java.io.StreamCorruptedException; |
| 30 | import java.io.Serializable; |
| 31 | import java.io.ObjectOutputStream; |
| 32 | import java.io.ObjectInputStream; |
| 33 | import java.lang.reflect.Method; |
| 34 | import java.util.Arrays; |
| 35 | import java.util.Map; |
| 36 | import java.util.WeakHashMap; |
| 37 | import java.security.AccessController; |
| 38 | import java.security.PrivilegedAction; |
| 39 | |
| 40 | import static javax.management.ImmutableDescriptor.nonNullDescriptor; |
| 41 | |
| 42 | /** |
| 43 | * <p>Describes the management interface exposed by an MBean; that is, |
| 44 | * the set of attributes and operations which are available for |
| 45 | * management operations. Instances of this class are immutable. |
| 46 | * Subclasses may be mutable but this is not recommended.</p> |
| 47 | * |
| 48 | * <p>The contents of the <code>MBeanInfo</code> for a Dynamic MBean |
| 49 | * are determined by its {@link DynamicMBean#getMBeanInfo |
| 50 | * getMBeanInfo()} method. This includes Open MBeans and Model |
| 51 | * MBeans, which are kinds of Dynamic MBeans.</p> |
| 52 | * |
| 53 | * <p>The contents of the <code>MBeanInfo</code> for a Standard MBean |
| 54 | * are determined by the MBean server as follows:</p> |
| 55 | * |
| 56 | * <ul> |
| 57 | * |
| 58 | * <li>{@link #getClassName()} returns the Java class name of the MBean |
| 59 | * object; |
| 60 | * |
| 61 | * <li>{@link #getConstructors()} returns the list of all public |
| 62 | * constructors in that object; |
| 63 | * |
| 64 | * <li>{@link #getAttributes()} returns the list of all attributes |
| 65 | * whose existence is deduced from the presence in the MBean interface |
| 66 | * of a <code>get<i>Name</i></code>, <code>is<i>Name</i></code>, or |
| 67 | * <code>set<i>Name</i></code> method that conforms to the conventions |
| 68 | * for Standard MBeans; |
| 69 | * |
| 70 | * <li>{@link #getOperations()} returns the list of all methods in |
| 71 | * the MBean interface that do not represent attributes; |
| 72 | * |
| 73 | * <li>{@link #getNotifications()} returns an empty array if the MBean |
| 74 | * does not implement the {@link NotificationBroadcaster} interface, |
| 75 | * otherwise the result of calling {@link |
| 76 | * NotificationBroadcaster#getNotificationInfo()} on it; |
| 77 | * |
| 78 | * <li>{@link #getDescriptor()} returns a descriptor containing the contents |
| 79 | * of any descriptor annotations in the MBean interface. |
| 80 | * |
| 81 | * </ul> |
| 82 | * |
| 83 | * <p>The description returned by {@link #getDescription()} and the |
| 84 | * descriptions of the contained attributes and operations are determined |
| 85 | * by the corresponding <!-- link here --> Description annotations if any; |
| 86 | * otherwise their contents are not specified.</p> |
| 87 | * |
| 88 | * <p>The remaining details of the <code>MBeanInfo</code> for a |
| 89 | * Standard MBean are not specified. This includes the description of |
| 90 | * any contained constructors, and notifications; the names |
| 91 | * of parameters to constructors and operations; and the descriptions of |
| 92 | * constructor parameters.</p> |
| 93 | * |
| 94 | * @since 1.5 |
| 95 | */ |
| 96 | public class MBeanInfo implements Cloneable, Serializable, DescriptorRead { |
| 97 | |
| 98 | /* Serial version */ |
| 99 | static final long serialVersionUID = -6451021435135161911L; |
| 100 | |
| 101 | /** |
| 102 | * @serial The Descriptor for the MBean. This field |
| 103 | * can be null, which is equivalent to an empty Descriptor. |
| 104 | */ |
| 105 | private transient Descriptor descriptor; |
| 106 | |
| 107 | /** |
| 108 | * @serial The human readable description of the class. |
| 109 | */ |
| 110 | private final String description; |
| 111 | |
| 112 | /** |
| 113 | * @serial The MBean qualified name. |
| 114 | */ |
| 115 | private final String className; |
| 116 | |
| 117 | /** |
| 118 | * @serial The MBean attribute descriptors. |
| 119 | */ |
| 120 | private final MBeanAttributeInfo[] attributes; |
| 121 | |
| 122 | /** |
| 123 | * @serial The MBean operation descriptors. |
| 124 | */ |
| 125 | private final MBeanOperationInfo[] operations; |
| 126 | |
| 127 | /** |
| 128 | * @serial The MBean constructor descriptors. |
| 129 | */ |
| 130 | private final MBeanConstructorInfo[] constructors; |
| 131 | |
| 132 | /** |
| 133 | * @serial The MBean notification descriptors. |
| 134 | */ |
| 135 | private final MBeanNotificationInfo[] notifications; |
| 136 | |
| 137 | private transient int hashCode; |
| 138 | |
| 139 | /** |
| 140 | * <p>True if this class is known not to override the array-valued |
| 141 | * getters of MBeanInfo. Obviously true for MBeanInfo itself, and true |
| 142 | * for a subclass where we succeed in reflecting on the methods |
| 143 | * and discover they are not overridden.</p> |
| 144 | * |
| 145 | * <p>The purpose of this variable is to avoid cloning the arrays |
| 146 | * when doing operations like {@link #equals} where we know they |
| 147 | * will not be changed. If a subclass overrides a getter, we |
| 148 | * cannot access the corresponding array directly.</p> |
| 149 | */ |
| 150 | private final transient boolean arrayGettersSafe; |
| 151 | |
| 152 | /** |
| 153 | * Constructs an <CODE>MBeanInfo</CODE>. |
| 154 | * |
| 155 | * @param className The name of the Java class of the MBean described |
| 156 | * by this <CODE>MBeanInfo</CODE>. This value may be any |
| 157 | * syntactically legal Java class name. It does not have to be a |
| 158 | * Java class known to the MBean server or to the MBean's |
| 159 | * ClassLoader. If it is a Java class known to the MBean's |
| 160 | * ClassLoader, it is recommended but not required that the |
| 161 | * class's public methods include those that would appear in a |
| 162 | * Standard MBean implementing the attributes and operations in |
| 163 | * this MBeanInfo. |
| 164 | * @param description A human readable description of the MBean (optional). |
| 165 | * @param attributes The list of exposed attributes of the MBean. |
| 166 | * This may be null with the same effect as a zero-length array. |
| 167 | * @param constructors The list of public constructors of the |
| 168 | * MBean. This may be null with the same effect as a zero-length |
| 169 | * array. |
| 170 | * @param operations The list of operations of the MBean. This |
| 171 | * may be null with the same effect as a zero-length array. |
| 172 | * @param notifications The list of notifications emitted. This |
| 173 | * may be null with the same effect as a zero-length array. |
| 174 | */ |
| 175 | public MBeanInfo(String className, |
| 176 | String description, |
| 177 | MBeanAttributeInfo[] attributes, |
| 178 | MBeanConstructorInfo[] constructors, |
| 179 | MBeanOperationInfo[] operations, |
| 180 | MBeanNotificationInfo[] notifications) |
| 181 | throws IllegalArgumentException { |
| 182 | this(className, description, attributes, constructors, operations, |
| 183 | notifications, null); |
| 184 | } |
| 185 | |
| 186 | /** |
| 187 | * Constructs an <CODE>MBeanInfo</CODE>. |
| 188 | * |
| 189 | * @param className The name of the Java class of the MBean described |
| 190 | * by this <CODE>MBeanInfo</CODE>. This value may be any |
| 191 | * syntactically legal Java class name. It does not have to be a |
| 192 | * Java class known to the MBean server or to the MBean's |
| 193 | * ClassLoader. If it is a Java class known to the MBean's |
| 194 | * ClassLoader, it is recommended but not required that the |
| 195 | * class's public methods include those that would appear in a |
| 196 | * Standard MBean implementing the attributes and operations in |
| 197 | * this MBeanInfo. |
| 198 | * @param description A human readable description of the MBean (optional). |
| 199 | * @param attributes The list of exposed attributes of the MBean. |
| 200 | * This may be null with the same effect as a zero-length array. |
| 201 | * @param constructors The list of public constructors of the |
| 202 | * MBean. This may be null with the same effect as a zero-length |
| 203 | * array. |
| 204 | * @param operations The list of operations of the MBean. This |
| 205 | * may be null with the same effect as a zero-length array. |
| 206 | * @param notifications The list of notifications emitted. This |
| 207 | * may be null with the same effect as a zero-length array. |
| 208 | * @param descriptor The descriptor for the MBean. This may be null |
| 209 | * which is equivalent to an empty descriptor. |
| 210 | * |
| 211 | * @since 1.6 |
| 212 | */ |
| 213 | public MBeanInfo(String className, |
| 214 | String description, |
| 215 | MBeanAttributeInfo[] attributes, |
| 216 | MBeanConstructorInfo[] constructors, |
| 217 | MBeanOperationInfo[] operations, |
| 218 | MBeanNotificationInfo[] notifications, |
| 219 | Descriptor descriptor) |
| 220 | throws IllegalArgumentException { |
| 221 | |
| 222 | this.className = className; |
| 223 | |
| 224 | this.description = description; |
| 225 | |
| 226 | if (attributes == null) |
| 227 | attributes = MBeanAttributeInfo.NO_ATTRIBUTES; |
| 228 | this.attributes = attributes; |
| 229 | |
| 230 | if (operations == null) |
| 231 | operations = MBeanOperationInfo.NO_OPERATIONS; |
| 232 | this.operations = operations; |
| 233 | |
| 234 | if (constructors == null) |
| 235 | constructors = MBeanConstructorInfo.NO_CONSTRUCTORS; |
| 236 | this.constructors = constructors; |
| 237 | |
| 238 | if (notifications == null) |
| 239 | notifications = MBeanNotificationInfo.NO_NOTIFICATIONS; |
| 240 | this.notifications = notifications; |
| 241 | |
| 242 | if (descriptor == null) |
| 243 | descriptor = ImmutableDescriptor.EMPTY_DESCRIPTOR; |
| 244 | this.descriptor = descriptor; |
| 245 | |
| 246 | this.arrayGettersSafe = |
| 247 | arrayGettersSafe(this.getClass(), MBeanInfo.class); |
| 248 | } |
| 249 | |
| 250 | /** |
| 251 | * <p>Returns a shallow clone of this instance. |
| 252 | * The clone is obtained by simply calling <tt>super.clone()</tt>, |
| 253 | * thus calling the default native shallow cloning mechanism |
| 254 | * implemented by <tt>Object.clone()</tt>. |
| 255 | * No deeper cloning of any internal field is made.</p> |
| 256 | * |
| 257 | * <p>Since this class is immutable, the clone method is chiefly of |
| 258 | * interest to subclasses.</p> |
| 259 | */ |
| 260 | public Object clone () { |
| 261 | try { |
| 262 | return super.clone() ; |
| 263 | } catch (CloneNotSupportedException e) { |
| 264 | // should not happen as this class is cloneable |
| 265 | return null; |
| 266 | } |
| 267 | } |
| 268 | |
| 269 | |
| 270 | /** |
| 271 | * Returns the name of the Java class of the MBean described by |
| 272 | * this <CODE>MBeanInfo</CODE>. |
| 273 | * |
| 274 | * @return the class name. |
| 275 | */ |
| 276 | public String getClassName() { |
| 277 | return className; |
| 278 | } |
| 279 | |
| 280 | /** |
| 281 | * Returns a human readable description of the MBean. |
| 282 | * |
| 283 | * @return the description. |
| 284 | */ |
| 285 | public String getDescription() { |
| 286 | return description; |
| 287 | } |
| 288 | |
| 289 | /** |
| 290 | * Returns the list of attributes exposed for management. |
| 291 | * Each attribute is described by an <CODE>MBeanAttributeInfo</CODE> object. |
| 292 | * |
| 293 | * The returned array is a shallow copy of the internal array, |
| 294 | * which means that it is a copy of the internal array of |
| 295 | * references to the <CODE>MBeanAttributeInfo</CODE> objects |
| 296 | * but that each referenced <CODE>MBeanAttributeInfo</CODE> object is not copied. |
| 297 | * |
| 298 | * @return An array of <CODE>MBeanAttributeInfo</CODE> objects. |
| 299 | */ |
| 300 | public MBeanAttributeInfo[] getAttributes() { |
| 301 | MBeanAttributeInfo[] as = nonNullAttributes(); |
| 302 | if (as.length == 0) |
| 303 | return as; |
| 304 | else |
| 305 | return as.clone(); |
| 306 | } |
| 307 | |
| 308 | private MBeanAttributeInfo[] fastGetAttributes() { |
| 309 | if (arrayGettersSafe) |
| 310 | return nonNullAttributes(); |
| 311 | else |
| 312 | return getAttributes(); |
| 313 | } |
| 314 | |
| 315 | /** |
| 316 | * Return the value of the attributes field, or an empty array if |
| 317 | * the field is null. This can't happen with a |
| 318 | * normally-constructed instance of this class, but can if the |
| 319 | * instance was deserialized from another implementation that |
| 320 | * allows the field to be null. It would be simpler if we enforced |
| 321 | * the class invariant that these fields cannot be null by writing |
| 322 | * a readObject() method, but that would require us to define the |
| 323 | * various array fields as non-final, which is annoying because |
| 324 | * conceptually they are indeed final. |
| 325 | */ |
| 326 | private MBeanAttributeInfo[] nonNullAttributes() { |
| 327 | return (attributes == null) ? |
| 328 | MBeanAttributeInfo.NO_ATTRIBUTES : attributes; |
| 329 | } |
| 330 | |
| 331 | /** |
| 332 | * Returns the list of operations of the MBean. |
| 333 | * Each operation is described by an <CODE>MBeanOperationInfo</CODE> object. |
| 334 | * |
| 335 | * The returned array is a shallow copy of the internal array, |
| 336 | * which means that it is a copy of the internal array of |
| 337 | * references to the <CODE>MBeanOperationInfo</CODE> objects |
| 338 | * but that each referenced <CODE>MBeanOperationInfo</CODE> object is not copied. |
| 339 | * |
| 340 | * @return An array of <CODE>MBeanOperationInfo</CODE> objects. |
| 341 | */ |
| 342 | public MBeanOperationInfo[] getOperations() { |
| 343 | MBeanOperationInfo[] os = nonNullOperations(); |
| 344 | if (os.length == 0) |
| 345 | return os; |
| 346 | else |
| 347 | return os.clone(); |
| 348 | } |
| 349 | |
| 350 | private MBeanOperationInfo[] fastGetOperations() { |
| 351 | if (arrayGettersSafe) |
| 352 | return nonNullOperations(); |
| 353 | else |
| 354 | return getOperations(); |
| 355 | } |
| 356 | |
| 357 | private MBeanOperationInfo[] nonNullOperations() { |
| 358 | return (operations == null) ? |
| 359 | MBeanOperationInfo.NO_OPERATIONS : operations; |
| 360 | } |
| 361 | |
| 362 | /** |
| 363 | * <p>Returns the list of the public constructors of the MBean. |
| 364 | * Each constructor is described by an |
| 365 | * <CODE>MBeanConstructorInfo</CODE> object.</p> |
| 366 | * |
| 367 | * <p>The returned array is a shallow copy of the internal array, |
| 368 | * which means that it is a copy of the internal array of |
| 369 | * references to the <CODE>MBeanConstructorInfo</CODE> objects but |
| 370 | * that each referenced <CODE>MBeanConstructorInfo</CODE> object |
| 371 | * is not copied.</p> |
| 372 | * |
| 373 | * <p>The returned list is not necessarily exhaustive. That is, |
| 374 | * the MBean may have a public constructor that is not in the |
| 375 | * list. In this case, the MBean server can construct another |
| 376 | * instance of this MBean's class using that constructor, even |
| 377 | * though it is not listed here.</p> |
| 378 | * |
| 379 | * @return An array of <CODE>MBeanConstructorInfo</CODE> objects. |
| 380 | */ |
| 381 | public MBeanConstructorInfo[] getConstructors() { |
| 382 | MBeanConstructorInfo[] cs = nonNullConstructors(); |
| 383 | if (cs.length == 0) |
| 384 | return cs; |
| 385 | else |
| 386 | return cs.clone(); |
| 387 | } |
| 388 | |
| 389 | private MBeanConstructorInfo[] fastGetConstructors() { |
| 390 | if (arrayGettersSafe) |
| 391 | return nonNullConstructors(); |
| 392 | else |
| 393 | return getConstructors(); |
| 394 | } |
| 395 | |
| 396 | private MBeanConstructorInfo[] nonNullConstructors() { |
| 397 | return (constructors == null) ? |
| 398 | MBeanConstructorInfo.NO_CONSTRUCTORS : constructors; |
| 399 | } |
| 400 | |
| 401 | /** |
| 402 | * Returns the list of the notifications emitted by the MBean. |
| 403 | * Each notification is described by an <CODE>MBeanNotificationInfo</CODE> object. |
| 404 | * |
| 405 | * The returned array is a shallow copy of the internal array, |
| 406 | * which means that it is a copy of the internal array of |
| 407 | * references to the <CODE>MBeanNotificationInfo</CODE> objects |
| 408 | * but that each referenced <CODE>MBeanNotificationInfo</CODE> object is not copied. |
| 409 | * |
| 410 | * @return An array of <CODE>MBeanNotificationInfo</CODE> objects. |
| 411 | */ |
| 412 | public MBeanNotificationInfo[] getNotifications() { |
| 413 | MBeanNotificationInfo[] ns = nonNullNotifications(); |
| 414 | if (ns.length == 0) |
| 415 | return ns; |
| 416 | else |
| 417 | return ns.clone(); |
| 418 | } |
| 419 | |
| 420 | private MBeanNotificationInfo[] fastGetNotifications() { |
| 421 | if (arrayGettersSafe) |
| 422 | return nonNullNotifications(); |
| 423 | else |
| 424 | return getNotifications(); |
| 425 | } |
| 426 | |
| 427 | private MBeanNotificationInfo[] nonNullNotifications() { |
| 428 | return (notifications == null) ? |
| 429 | MBeanNotificationInfo.NO_NOTIFICATIONS : notifications; |
| 430 | } |
| 431 | |
| 432 | /** |
| 433 | * Get the descriptor of this MBeanInfo. Changing the returned value |
| 434 | * will have no affect on the original descriptor. |
| 435 | * |
| 436 | * @return a descriptor that is either immutable or a copy of the original. |
| 437 | * |
| 438 | * @since 1.6 |
| 439 | */ |
| 440 | public Descriptor getDescriptor() { |
| 441 | return (Descriptor) nonNullDescriptor(descriptor).clone(); |
| 442 | } |
| 443 | |
| 444 | public String toString() { |
| 445 | return |
| 446 | getClass().getName() + "[" + |
| 447 | "description=" + getDescription() + ", " + |
| 448 | "attributes=" + Arrays.asList(fastGetAttributes()) + ", " + |
| 449 | "constructors=" + Arrays.asList(fastGetConstructors()) + ", " + |
| 450 | "operations=" + Arrays.asList(fastGetOperations()) + ", " + |
| 451 | "notifications=" + Arrays.asList(fastGetNotifications()) + ", " + |
| 452 | "descriptor=" + getDescriptor() + |
| 453 | "]"; |
| 454 | } |
| 455 | |
| 456 | /** |
| 457 | * <p>Compare this MBeanInfo to another. Two MBeanInfo objects |
| 458 | * are equal if and only if they return equal values for {@link |
| 459 | * #getClassName()}, for {@link #getDescription()}, and for |
| 460 | * {@link #getDescriptor()}, and the |
| 461 | * arrays returned by the two objects for {@link |
| 462 | * #getAttributes()}, {@link #getOperations()}, {@link |
| 463 | * #getConstructors()}, and {@link #getNotifications()} are |
| 464 | * pairwise equal. Here "equal" means {@link |
| 465 | * Object#equals(Object)}, not identity.</p> |
| 466 | * |
| 467 | * <p>If two MBeanInfo objects return the same values in one of |
| 468 | * their arrays but in a different order then they are not equal.</p> |
| 469 | * |
| 470 | * @param o the object to compare to. |
| 471 | * |
| 472 | * @return true if and only if <code>o</code> is an MBeanInfo that is equal |
| 473 | * to this one according to the rules above. |
| 474 | */ |
| 475 | public boolean equals(Object o) { |
| 476 | if (o == this) |
| 477 | return true; |
| 478 | if (!(o instanceof MBeanInfo)) |
| 479 | return false; |
| 480 | MBeanInfo p = (MBeanInfo) o; |
| 481 | if (!isEqual(getClassName(), p.getClassName()) || |
| 482 | !isEqual(getDescription(), p.getDescription()) || |
| 483 | !getDescriptor().equals(p.getDescriptor())) { |
| 484 | return false; |
| 485 | } |
| 486 | |
| 487 | return |
| 488 | (Arrays.equals(p.fastGetAttributes(), fastGetAttributes()) && |
| 489 | Arrays.equals(p.fastGetOperations(), fastGetOperations()) && |
| 490 | Arrays.equals(p.fastGetConstructors(), fastGetConstructors()) && |
| 491 | Arrays.equals(p.fastGetNotifications(), fastGetNotifications())); |
| 492 | } |
| 493 | |
| 494 | public int hashCode() { |
| 495 | /* Since computing the hashCode is quite expensive, we cache it. |
| 496 | If by some terrible misfortune the computed value is 0, the |
| 497 | caching won't work and we will recompute it every time. |
| 498 | |
| 499 | We don't bother synchronizing, because, at worst, n different |
| 500 | threads will compute the same hashCode at the same time. */ |
| 501 | if (hashCode != 0) |
| 502 | return hashCode; |
| 503 | |
| 504 | hashCode = |
| 505 | getClassName().hashCode() ^ |
| 506 | getDescriptor().hashCode() ^ |
| 507 | arrayHashCode(fastGetAttributes()) ^ |
| 508 | arrayHashCode(fastGetOperations()) ^ |
| 509 | arrayHashCode(fastGetConstructors()) ^ |
| 510 | arrayHashCode(fastGetNotifications()); |
| 511 | |
| 512 | return hashCode; |
| 513 | } |
| 514 | |
| 515 | private static int arrayHashCode(Object[] array) { |
| 516 | int hash = 0; |
| 517 | for (int i = 0; i < array.length; i++) |
| 518 | hash ^= array[i].hashCode(); |
| 519 | return hash; |
| 520 | } |
| 521 | |
| 522 | /** |
| 523 | * Cached results of previous calls to arrayGettersSafe. This is |
| 524 | * a WeakHashMap so that we don't prevent a class from being |
| 525 | * garbage collected just because we know whether it's immutable. |
| 526 | */ |
| 527 | private static final Map<Class, Boolean> arrayGettersSafeMap = |
| 528 | new WeakHashMap<Class, Boolean>(); |
| 529 | |
| 530 | /** |
| 531 | * Return true if <code>subclass</code> is known to preserve the |
| 532 | * immutability of <code>immutableClass</code>. The class |
| 533 | * <code>immutableClass</code> is a reference class that is known |
| 534 | * to be immutable. The subclass <code>subclass</code> is |
| 535 | * considered immutable if it does not override any public method |
| 536 | * of <code>immutableClass</code> whose name begins with "get". |
| 537 | * This is obviously not an infallible test for immutability, |
| 538 | * but it works for the public interfaces of the MBean*Info classes. |
| 539 | */ |
| 540 | static boolean arrayGettersSafe(Class subclass, Class immutableClass) { |
| 541 | if (subclass == immutableClass) |
| 542 | return true; |
| 543 | synchronized (arrayGettersSafeMap) { |
| 544 | Boolean safe = arrayGettersSafeMap.get(subclass); |
| 545 | if (safe == null) { |
| 546 | try { |
| 547 | ArrayGettersSafeAction action = |
| 548 | new ArrayGettersSafeAction(subclass, immutableClass); |
| 549 | safe = AccessController.doPrivileged(action); |
| 550 | } catch (Exception e) { // e.g. SecurityException |
| 551 | /* We don't know, so we assume it isn't. */ |
| 552 | safe = false; |
| 553 | } |
| 554 | arrayGettersSafeMap.put(subclass, safe); |
| 555 | } |
| 556 | return safe; |
| 557 | } |
| 558 | } |
| 559 | |
| 560 | /* |
| 561 | * The PrivilegedAction stuff is probably overkill. We can be |
| 562 | * pretty sure the caller does have the required privileges -- a |
| 563 | * JMX user that can't do reflection can't even use Standard |
| 564 | * MBeans! But there's probably a performance gain by not having |
| 565 | * to check the whole call stack. |
| 566 | */ |
| 567 | private static class ArrayGettersSafeAction |
| 568 | implements PrivilegedAction<Boolean> { |
| 569 | |
| 570 | private final Class<?> subclass; |
| 571 | private final Class<?> immutableClass; |
| 572 | |
| 573 | ArrayGettersSafeAction(Class<?> subclass, Class<?> immutableClass) { |
| 574 | this.subclass = subclass; |
| 575 | this.immutableClass = immutableClass; |
| 576 | } |
| 577 | |
| 578 | public Boolean run() { |
| 579 | Method[] methods = immutableClass.getMethods(); |
| 580 | for (int i = 0; i < methods.length; i++) { |
| 581 | Method method = methods[i]; |
| 582 | String methodName = method.getName(); |
| 583 | if (methodName.startsWith("get") && |
| 584 | method.getParameterTypes().length == 0 && |
| 585 | method.getReturnType().isArray()) { |
| 586 | try { |
| 587 | Method submethod = |
| 588 | subclass.getMethod(methodName); |
| 589 | if (!submethod.equals(method)) |
| 590 | return false; |
| 591 | } catch (NoSuchMethodException e) { |
| 592 | return false; |
| 593 | } |
| 594 | } |
| 595 | } |
| 596 | return true; |
| 597 | } |
| 598 | } |
| 599 | |
| 600 | private static boolean isEqual(String s1, String s2) { |
| 601 | boolean ret; |
| 602 | |
| 603 | if (s1 == null) { |
| 604 | ret = (s2 == null); |
| 605 | } else { |
| 606 | ret = s1.equals(s2); |
| 607 | } |
| 608 | |
| 609 | return ret; |
| 610 | } |
| 611 | |
| 612 | /** |
| 613 | * Serializes an {@link MBeanInfo} to an {@link ObjectOutputStream}. |
| 614 | * @serialData |
| 615 | * For compatibility reasons, an object of this class is serialized as follows. |
| 616 | * <ul> |
| 617 | * The method {@link ObjectOutputStream#defaultWriteObject defaultWriteObject()} |
| 618 | * is called first to serialize the object except the field {@code descriptor} |
| 619 | * which is declared as transient. The field {@code descriptor} is serialized |
| 620 | * as follows: |
| 621 | * <ul> |
| 622 | * <li> If {@code descriptor} is an instance of the class |
| 623 | * {@link ImmutableDescriptor}, the method {@link ObjectOutputStream#write |
| 624 | * write(int val)} is called to write a byte with the value {@code 1}, |
| 625 | * then the method {@link ObjectOutputStream#writeObject writeObject(Object obj)} |
| 626 | * is called twice to serialize the field names and the field values of the |
| 627 | * {@code descriptor}, respectively as a {@code String[]} and an |
| 628 | * {@code Object[]};</li> |
| 629 | * <li> Otherwise, the method {@link ObjectOutputStream#write write(int val)} |
| 630 | * is called to write a byte with the value {@code 0}, then the method |
| 631 | * {@link ObjectOutputStream#writeObject writeObject(Object obj)} is called |
| 632 | * to serialize the field {@code descriptor} directly. |
| 633 | * </ul> |
| 634 | * </ul> |
| 635 | * @since 1.6 |
| 636 | */ |
| 637 | private void writeObject(ObjectOutputStream out) throws IOException { |
| 638 | out.defaultWriteObject(); |
| 639 | |
| 640 | if (descriptor.getClass() == ImmutableDescriptor.class) { |
| 641 | out.write(1); |
| 642 | |
| 643 | final String[] names = descriptor.getFieldNames(); |
| 644 | |
| 645 | out.writeObject(names); |
| 646 | out.writeObject(descriptor.getFieldValues(names)); |
| 647 | } else { |
| 648 | out.write(0); |
| 649 | |
| 650 | out.writeObject(descriptor); |
| 651 | } |
| 652 | } |
| 653 | |
| 654 | /** |
| 655 | * Deserializes an {@link MBeanInfo} from an {@link ObjectInputStream}. |
| 656 | * @serialData |
| 657 | * For compatibility reasons, an object of this class is deserialized as follows. |
| 658 | * <ul> |
| 659 | * The method {@link ObjectInputStream#defaultReadObject defaultReadObject()} |
| 660 | * is called first to deserialize the object except the field |
| 661 | * {@code descriptor}, which is not serialized in the default way. Then the method |
| 662 | * {@link ObjectInputStream#read read()} is called to read a byte, the field |
| 663 | * {@code descriptor} is deserialized according to the value of the byte value: |
| 664 | * <ul> |
| 665 | * <li>1. The method {@link ObjectInputStream#readObject readObject()} |
| 666 | * is called twice to obtain the field names (a {@code String[]}) and |
| 667 | * the field values (a {@code Object[]}) of the {@code descriptor}. |
| 668 | * The two obtained values then are used to construct |
| 669 | * an {@link ImmutableDescriptor} instance for the field |
| 670 | * {@code descriptor};</li> |
| 671 | * <li>0. The value for the field {@code descriptor} is obtained directly |
| 672 | * by calling the method {@link ObjectInputStream#readObject readObject()}. |
| 673 | * If the obtained value is null, the field {@code descriptor} is set to |
| 674 | * {@link ImmutableDescriptor#EMPTY_DESCRIPTOR EMPTY_DESCRIPTOR};</li> |
| 675 | * <li>-1. This means that there is no byte to read and that the object is from |
| 676 | * an earlier version of the JMX API. The field {@code descriptor} is set to |
| 677 | * {@link ImmutableDescriptor#EMPTY_DESCRIPTOR EMPTY_DESCRIPTOR}.</li> |
| 678 | * <li>Any other value. A {@link StreamCorruptedException} is thrown.</li> |
| 679 | * </ul> |
| 680 | * </ul> |
| 681 | * @since 1.6 |
| 682 | */ |
| 683 | |
| 684 | private void readObject(ObjectInputStream in) |
| 685 | throws IOException, ClassNotFoundException { |
| 686 | |
| 687 | in.defaultReadObject(); |
| 688 | |
| 689 | switch (in.read()) { |
| 690 | case 1: |
| 691 | final String[] names = (String[])in.readObject(); |
| 692 | |
| 693 | if (names.length == 0) { |
| 694 | descriptor = ImmutableDescriptor.EMPTY_DESCRIPTOR; |
| 695 | } else { |
| 696 | final Object[] values = (Object[])in.readObject(); |
| 697 | descriptor = new ImmutableDescriptor(names, values); |
| 698 | } |
| 699 | |
| 700 | break; |
| 701 | case 0: |
| 702 | descriptor = (Descriptor)in.readObject(); |
| 703 | |
| 704 | if (descriptor == null) { |
| 705 | descriptor = ImmutableDescriptor.EMPTY_DESCRIPTOR; |
| 706 | } |
| 707 | |
| 708 | break; |
| 709 | case -1: // from an earlier version of the JMX API |
| 710 | descriptor = ImmutableDescriptor.EMPTY_DESCRIPTOR; |
| 711 | |
| 712 | break; |
| 713 | default: |
| 714 | throw new StreamCorruptedException("Got unexpected byte."); |
| 715 | } |
| 716 | } |
| 717 | } |