J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2000-2007 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 | |
| 27 | package javax.management.openmbean; |
| 28 | |
| 29 | |
| 30 | // java import |
| 31 | // |
| 32 | import java.util.Arrays; |
| 33 | import java.util.HashSet; |
| 34 | |
| 35 | import javax.management.Descriptor; |
| 36 | import javax.management.MBeanAttributeInfo; |
| 37 | import javax.management.MBeanConstructorInfo; |
| 38 | import javax.management.MBeanInfo; |
| 39 | import javax.management.MBeanNotificationInfo; |
| 40 | import javax.management.MBeanOperationInfo; |
| 41 | |
| 42 | /** |
| 43 | * The {@code OpenMBeanInfoSupport} class describes the management |
| 44 | * information of an <i>open MBean</i>: it is a subclass of {@link |
| 45 | * javax.management.MBeanInfo}, and it implements the {@link |
| 46 | * OpenMBeanInfo} interface. Note that an <i>open MBean</i> is |
| 47 | * recognized as such if its {@code getMBeanInfo()} method returns an |
| 48 | * instance of a class which implements the OpenMBeanInfo interface, |
| 49 | * typically {@code OpenMBeanInfoSupport}. |
| 50 | * |
| 51 | * |
| 52 | * @since 1.5 |
| 53 | */ |
| 54 | public class OpenMBeanInfoSupport |
| 55 | extends MBeanInfo |
| 56 | implements OpenMBeanInfo { |
| 57 | |
| 58 | /* Serial version */ |
| 59 | static final long serialVersionUID = 4349395935420511492L; |
| 60 | |
| 61 | // As this instance is immutable, these two values |
| 62 | // need only be calculated once. |
| 63 | private transient Integer myHashCode = null; |
| 64 | private transient String myToString = null; |
| 65 | |
| 66 | |
| 67 | /** |
| 68 | * <p>Constructs an {@code OpenMBeanInfoSupport} instance, which |
| 69 | * describes a class of open MBeans with the specified {@code |
| 70 | * className}, {@code description}, {@code openAttributes}, {@code |
| 71 | * openConstructors} , {@code openOperations} and {@code |
| 72 | * notifications}.</p> |
| 73 | * |
| 74 | * <p>The {@code openAttributes}, {@code openConstructors}, |
| 75 | * {@code openOperations} and {@code notifications} |
| 76 | * array parameters are internally copied, so that subsequent changes |
| 77 | * to the arrays referenced by these parameters have no effect on this |
| 78 | * instance.</p> |
| 79 | * |
| 80 | * @param className The fully qualified Java class name of the |
| 81 | * open MBean described by this <CODE>OpenMBeanInfoSupport</CODE> |
| 82 | * instance. |
| 83 | * |
| 84 | * @param description A human readable description of the open |
| 85 | * MBean described by this <CODE>OpenMBeanInfoSupport</CODE> |
| 86 | * instance. |
| 87 | * |
| 88 | * @param openAttributes The list of exposed attributes of the |
| 89 | * described open MBean; Must be an array of instances of a |
| 90 | * subclass of {@code MBeanAttributeInfo}, typically {@code |
| 91 | * OpenMBeanAttributeInfoSupport}. |
| 92 | * |
| 93 | * @param openConstructors The list of exposed public constructors |
| 94 | * of the described open MBean; Must be an array of instances of a |
| 95 | * subclass of {@code MBeanConstructorInfo}, typically {@code |
| 96 | * OpenMBeanConstructorInfoSupport}. |
| 97 | * |
| 98 | * @param openOperations The list of exposed operations of the |
| 99 | * described open MBean. Must be an array of instances of a |
| 100 | * subclass of {@code MBeanOperationInfo}, typically {@code |
| 101 | * OpenMBeanOperationInfoSupport}. |
| 102 | * |
| 103 | * @param notifications The list of notifications emitted by the |
| 104 | * described open MBean. |
| 105 | * |
| 106 | * @throws ArrayStoreException If {@code openAttributes}, {@code |
| 107 | * openConstructors} or {@code openOperations} is not an array of |
| 108 | * instances of a subclass of {@code MBeanAttributeInfo}, {@code |
| 109 | * MBeanConstructorInfo} or {@code MBeanOperationInfo} |
| 110 | * respectively. |
| 111 | */ |
| 112 | public OpenMBeanInfoSupport(String className, |
| 113 | String description, |
| 114 | OpenMBeanAttributeInfo[] openAttributes, |
| 115 | OpenMBeanConstructorInfo[] openConstructors, |
| 116 | OpenMBeanOperationInfo[] openOperations, |
| 117 | MBeanNotificationInfo[] notifications) { |
| 118 | this(className, description, |
| 119 | openAttributes, openConstructors, openOperations, notifications, |
| 120 | (Descriptor) null); |
| 121 | } |
| 122 | |
| 123 | /** |
| 124 | * <p>Constructs an {@code OpenMBeanInfoSupport} instance, which |
| 125 | * describes a class of open MBeans with the specified {@code |
| 126 | * className}, {@code description}, {@code openAttributes}, {@code |
| 127 | * openConstructors} , {@code openOperations}, {@code |
| 128 | * notifications}, and {@code descriptor}.</p> |
| 129 | * |
| 130 | * <p>The {@code openAttributes}, {@code openConstructors}, {@code |
| 131 | * openOperations} and {@code notifications} array parameters are |
| 132 | * internally copied, so that subsequent changes to the arrays |
| 133 | * referenced by these parameters have no effect on this |
| 134 | * instance.</p> |
| 135 | * |
| 136 | * @param className The fully qualified Java class name of the |
| 137 | * open MBean described by this <CODE>OpenMBeanInfoSupport</CODE> |
| 138 | * instance. |
| 139 | * |
| 140 | * @param description A human readable description of the open |
| 141 | * MBean described by this <CODE>OpenMBeanInfoSupport</CODE> |
| 142 | * instance. |
| 143 | * |
| 144 | * @param openAttributes The list of exposed attributes of the |
| 145 | * described open MBean; Must be an array of instances of a |
| 146 | * subclass of {@code MBeanAttributeInfo}, typically {@code |
| 147 | * OpenMBeanAttributeInfoSupport}. |
| 148 | * |
| 149 | * @param openConstructors The list of exposed public constructors |
| 150 | * of the described open MBean; Must be an array of instances of a |
| 151 | * subclass of {@code MBeanConstructorInfo}, typically {@code |
| 152 | * OpenMBeanConstructorInfoSupport}. |
| 153 | * |
| 154 | * @param openOperations The list of exposed operations of the |
| 155 | * described open MBean. Must be an array of instances of a |
| 156 | * subclass of {@code MBeanOperationInfo}, typically {@code |
| 157 | * OpenMBeanOperationInfoSupport}. |
| 158 | * |
| 159 | * @param notifications The list of notifications emitted by the |
| 160 | * described open MBean. |
| 161 | * |
| 162 | * @param descriptor The descriptor for the MBean. This may be null |
| 163 | * which is equivalent to an empty descriptor. |
| 164 | * |
| 165 | * @throws ArrayStoreException If {@code openAttributes}, {@code |
| 166 | * openConstructors} or {@code openOperations} is not an array of |
| 167 | * instances of a subclass of {@code MBeanAttributeInfo}, {@code |
| 168 | * MBeanConstructorInfo} or {@code MBeanOperationInfo} |
| 169 | * respectively. |
| 170 | * |
| 171 | * @since 1.6 |
| 172 | */ |
| 173 | public OpenMBeanInfoSupport(String className, |
| 174 | String description, |
| 175 | OpenMBeanAttributeInfo[] openAttributes, |
| 176 | OpenMBeanConstructorInfo[] openConstructors, |
| 177 | OpenMBeanOperationInfo[] openOperations, |
| 178 | MBeanNotificationInfo[] notifications, |
| 179 | Descriptor descriptor) { |
| 180 | super(className, |
| 181 | description, |
| 182 | attributeArray(openAttributes), |
| 183 | constructorArray(openConstructors), |
| 184 | operationArray(openOperations), |
| 185 | (notifications == null) ? null : notifications.clone(), |
| 186 | descriptor); |
| 187 | } |
| 188 | |
| 189 | |
| 190 | private static MBeanAttributeInfo[] |
| 191 | attributeArray(OpenMBeanAttributeInfo[] src) { |
| 192 | if (src == null) |
| 193 | return null; |
| 194 | MBeanAttributeInfo[] dst = new MBeanAttributeInfo[src.length]; |
| 195 | System.arraycopy(src, 0, dst, 0, src.length); |
| 196 | // may throw an ArrayStoreException |
| 197 | return dst; |
| 198 | } |
| 199 | |
| 200 | private static MBeanConstructorInfo[] |
| 201 | constructorArray(OpenMBeanConstructorInfo[] src) { |
| 202 | if (src == null) |
| 203 | return null; |
| 204 | MBeanConstructorInfo[] dst = new MBeanConstructorInfo[src.length]; |
| 205 | System.arraycopy(src, 0, dst, 0, src.length); |
| 206 | // may throw an ArrayStoreException |
| 207 | return dst; |
| 208 | } |
| 209 | |
| 210 | private static MBeanOperationInfo[] |
| 211 | operationArray(OpenMBeanOperationInfo[] src) { |
| 212 | if (src == null) |
| 213 | return null; |
| 214 | MBeanOperationInfo[] dst = new MBeanOperationInfo[src.length]; |
| 215 | System.arraycopy(src, 0, dst, 0, src.length); |
| 216 | return dst; |
| 217 | } |
| 218 | |
| 219 | |
| 220 | |
| 221 | /* *** Commodity methods from java.lang.Object *** */ |
| 222 | |
| 223 | |
| 224 | /** |
| 225 | * <p>Compares the specified {@code obj} parameter with this |
| 226 | * {@code OpenMBeanInfoSupport} instance for equality.</p> |
| 227 | * |
| 228 | * <p>Returns {@code true} if and only if all of the following |
| 229 | * statements are true: |
| 230 | * |
| 231 | * <ul> |
| 232 | * <li>{@code obj} is non null,</li> |
| 233 | * <li>{@code obj} also implements the {@code OpenMBeanInfo} |
| 234 | * interface,</li> |
| 235 | * <li>their class names are equal</li> |
| 236 | * <li>their infos on attributes, constructors, operations and |
| 237 | * notifications are equal</li> |
| 238 | * </ul> |
| 239 | * |
| 240 | * This ensures that this {@code equals} method works properly for |
| 241 | * {@code obj} parameters which are different implementations of |
| 242 | * the {@code OpenMBeanInfo} interface. |
| 243 | * |
| 244 | * @param obj the object to be compared for equality with this |
| 245 | * {@code OpenMBeanInfoSupport} instance; |
| 246 | * |
| 247 | * @return {@code true} if the specified object is equal to this |
| 248 | * {@code OpenMBeanInfoSupport} instance. |
| 249 | */ |
| 250 | public boolean equals(Object obj) { |
| 251 | |
| 252 | // if obj is null, return false |
| 253 | // |
| 254 | if (obj == null) { |
| 255 | return false; |
| 256 | } |
| 257 | |
| 258 | // if obj is not a OpenMBeanInfo, return false |
| 259 | // |
| 260 | OpenMBeanInfo other; |
| 261 | try { |
| 262 | other = (OpenMBeanInfo) obj; |
| 263 | } catch (ClassCastException e) { |
| 264 | return false; |
| 265 | } |
| 266 | |
| 267 | // Now, really test for equality between this OpenMBeanInfo |
| 268 | // implementation and the other: |
| 269 | // |
| 270 | |
| 271 | // their MBean className should be equal |
| 272 | if ( ! this.getClassName().equals(other.getClassName()) ) |
| 273 | return false; |
| 274 | |
| 275 | // their infos on attributes should be equal (order not |
| 276 | // significant => equality between sets, not arrays or lists) |
| 277 | if (!sameArrayContents(this.getAttributes(), other.getAttributes())) |
| 278 | return false; |
| 279 | |
| 280 | // their infos on constructors should be equal (order not |
| 281 | // significant => equality between sets, not arrays or lists) |
| 282 | if (!sameArrayContents(this.getConstructors(), other.getConstructors())) |
| 283 | return false; |
| 284 | |
| 285 | // their infos on operations should be equal (order not |
| 286 | // significant => equality between sets, not arrays or lists) |
| 287 | if (!sameArrayContents(this.getOperations(), other.getOperations())) |
| 288 | |
| 289 | return false; |
| 290 | |
| 291 | // their infos on notifications should be equal (order not |
| 292 | // significant => equality between sets, not arrays or lists) |
| 293 | if (!sameArrayContents(this.getNotifications(), other.getNotifications())) |
| 294 | return false; |
| 295 | |
| 296 | // All tests for equality were successful |
| 297 | // |
| 298 | return true; |
| 299 | } |
| 300 | |
| 301 | private static <T> boolean sameArrayContents(T[] a1, T[] a2) { |
| 302 | return (new HashSet<T>(Arrays.asList(a1)) |
| 303 | .equals(new HashSet<T>(Arrays.asList(a2)))); |
| 304 | } |
| 305 | |
| 306 | /** |
| 307 | * <p>Returns the hash code value for this {@code |
| 308 | * OpenMBeanInfoSupport} instance.</p> |
| 309 | * |
| 310 | * <p>The hash code of an {@code OpenMBeanInfoSupport} instance is |
| 311 | * the sum of the hash codes of all elements of information used |
| 312 | * in {@code equals} comparisons (ie: its class name, and its |
| 313 | * infos on attributes, constructors, operations and |
| 314 | * notifications, where the hashCode of each of these arrays is |
| 315 | * calculated by a call to {@code new |
| 316 | * java.util.HashSet(java.util.Arrays.asList(this.getSignature)).hashCode()}).</p> |
| 317 | * |
| 318 | * <p>This ensures that {@code t1.equals(t2)} implies that {@code |
| 319 | * t1.hashCode()==t2.hashCode()} for any two {@code |
| 320 | * OpenMBeanInfoSupport} instances {@code t1} and {@code t2}, as |
| 321 | * required by the general contract of the method {@link |
| 322 | * Object#hashCode() Object.hashCode()}.</p> |
| 323 | * |
| 324 | * <p>However, note that another instance of a class implementing |
| 325 | * the {@code OpenMBeanInfo} interface may be equal to this {@code |
| 326 | * OpenMBeanInfoSupport} instance as defined by {@link |
| 327 | * #equals(java.lang.Object)}, but may have a different hash code |
| 328 | * if it is calculated differently.</p> |
| 329 | * |
| 330 | * <p>As {@code OpenMBeanInfoSupport} instances are immutable, the |
| 331 | * hash code for this instance is calculated once, on the first |
| 332 | * call to {@code hashCode}, and then the same value is returned |
| 333 | * for subsequent calls.</p> |
| 334 | * |
| 335 | * @return the hash code value for this {@code |
| 336 | * OpenMBeanInfoSupport} instance |
| 337 | */ |
| 338 | public int hashCode() { |
| 339 | |
| 340 | // Calculate the hash code value if it has not yet been done |
| 341 | // (ie 1st call to hashCode()) |
| 342 | // |
| 343 | if (myHashCode == null) { |
| 344 | int value = 0; |
| 345 | value += this.getClassName().hashCode(); |
| 346 | value += arraySetHash(this.getAttributes()); |
| 347 | value += arraySetHash(this.getConstructors()); |
| 348 | value += arraySetHash(this.getOperations()); |
| 349 | value += arraySetHash(this.getNotifications()); |
| 350 | myHashCode = new Integer(value); |
| 351 | } |
| 352 | |
| 353 | // return always the same hash code for this instance (immutable) |
| 354 | // |
| 355 | return myHashCode.intValue(); |
| 356 | } |
| 357 | |
| 358 | private static <T> int arraySetHash(T[] a) { |
| 359 | return new HashSet<T>(Arrays.asList(a)).hashCode(); |
| 360 | } |
| 361 | |
| 362 | |
| 363 | |
| 364 | /** |
| 365 | * <p>Returns a string representation of this {@code |
| 366 | * OpenMBeanInfoSupport} instance.</p> |
| 367 | * |
| 368 | * <p>The string representation consists of the name of this class |
| 369 | * (ie {@code javax.management.openmbean.OpenMBeanInfoSupport}), |
| 370 | * the MBean class name, the string representation of infos on |
| 371 | * attributes, constructors, operations and notifications of the |
| 372 | * described MBean and the string representation of the descriptor.</p> |
| 373 | * |
| 374 | * <p>As {@code OpenMBeanInfoSupport} instances are immutable, the |
| 375 | * string representation for this instance is calculated once, on |
| 376 | * the first call to {@code toString}, and then the same value is |
| 377 | * returned for subsequent calls.</p> |
| 378 | * |
| 379 | * @return a string representation of this {@code |
| 380 | * OpenMBeanInfoSupport} instance |
| 381 | */ |
| 382 | public String toString() { |
| 383 | |
| 384 | // Calculate the string value if it has not yet been done (ie |
| 385 | // 1st call to toString()) |
| 386 | // |
| 387 | if (myToString == null) { |
| 388 | myToString = new StringBuilder() |
| 389 | .append(this.getClass().getName()) |
| 390 | .append("(mbean_class_name=") |
| 391 | .append(this.getClassName()) |
| 392 | .append(",attributes=") |
| 393 | .append(Arrays.asList(this.getAttributes()).toString()) |
| 394 | .append(",constructors=") |
| 395 | .append(Arrays.asList(this.getConstructors()).toString()) |
| 396 | .append(",operations=") |
| 397 | .append(Arrays.asList(this.getOperations()).toString()) |
| 398 | .append(",notifications=") |
| 399 | .append(Arrays.asList(this.getNotifications()).toString()) |
| 400 | .append(",descriptor=") |
| 401 | .append(this.getDescriptor()) |
| 402 | .append(")") |
| 403 | .toString(); |
| 404 | } |
| 405 | |
| 406 | // return always the same string representation for this |
| 407 | // instance (immutable) |
| 408 | // |
| 409 | return myToString; |
| 410 | } |
| 411 | |
| 412 | } |