1 /* 2 * Copyright (c) 2000, 2008, 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 * @author IBM Corp. 27 * 28 * Copyright IBM Corp. 1999-2000. All rights reserved. 29 */ 30 31 package javax.management; 32 33 import java.io.Serializable; 34 35 // Javadoc imports: 36 import java.lang.management.MemoryUsage; 37 import java.util.Arrays; 38 import java.util.Locale; 39 import java.util.ResourceBundle; 40 import javax.management.openmbean.CompositeData; 41 import javax.management.openmbean.OpenMBeanAttributeInfoSupport; 42 import javax.management.openmbean.OpenMBeanOperationInfoSupport; 43 import javax.management.openmbean.OpenMBeanParameterInfoSupport; 44 import javax.management.openmbean.OpenType; 45 46 /** 47 * <p>Additional metadata for a JMX element. A {@code Descriptor} 48 * is associated with a {@link MBeanInfo}, {@link MBeanAttributeInfo}, etc. 49 * It consists of a collection of fields. A field is a name and an 50 * associated value.</p> 51 * 52 * <p>Field names are not case-sensitive. The names {@code descriptorType}, 53 * {@code descriptortype}, and {@code DESCRIPTORTYPE} are all equivalent. 54 * However, the case that was used when the field was first set is preserved 55 * in the result of the {@link #getFields} and {@link #getFieldNames} 56 * methods.</p> 57 * 58 * <p>Not all field names and values are predefined. 59 * New fields can be defined and added by any program.</p> 60 * 61 * <p>A descriptor can be mutable or immutable. 62 * An immutable descriptor, once created, never changes. 63 * The <code>Descriptor</code> methods that could modify the contents 64 * of the descriptor will throw an exception 65 * for an immutable descriptor. Immutable descriptors are usually 66 * instances of {@link ImmutableDescriptor} or a subclass. Mutable 67 * descriptors are usually instances of 68 * {@link javax.management.modelmbean.DescriptorSupport} or a subclass. 69 * 70 * <p>Certain fields are used by the JMX implementation. This means 71 * either that the presence of the field may change the behavior of 72 * the JMX API or that the field may be set in descriptors returned by 73 * the JMX API. These fields appear in <i>italics</i> in the table 74 * below, and each one has a corresponding constant in the {@link JMX} 75 * class. For example, the field {@code defaultValue} is represented 76 * by the constant {@link JMX#DEFAULT_VALUE_FIELD}.</p> 77 * 78 * <p>Certain other fields have conventional meanings described in the 79 * table below but they are not required to be understood or set by 80 * the JMX implementation.</p> 81 * 82 * <p>Field names defined by the JMX specification in this and all 83 * future versions will never contain a period (.). Users can safely 84 * create their own fields by including a period in the name and be 85 * sure that these names will not collide with any future version of 86 * the JMX API. It is recommended to follow the Java package naming 87 * convention to avoid collisions between field names from different 88 * origins. For example, a field created by {@code example.com} might 89 * have the name {@code com.example.interestLevel}.</p> 90 * 91 * <p>Note that the values in the {@code defaultValue}, {@code 92 * legalValues}, {@code maxValue}, and {@code minValue} fields should 93 * be consistent with the type returned by the {@code getType()} 94 * method for the associated {@code MBeanAttributeInfo} or {@code 95 * MBeanParameterInfo}. For MXBeans, this means that they should be 96 * of the mapped Java type, called <em>opendata</em>(J) in the <a 97 * href="MXBean.html#mapping-rules">MXBean type mapping rules</a>.</p> 98 * 99 * <table border="1" cellpadding="5"> 100 * 101 * <tr><th>Name</th><th>Type</th><th>Used in</th><th>Meaning</th></tr> 102 * 103 * <tr id="defaultValue"><td><i>defaultValue</i><td>Object</td> 104 * <td>MBeanAttributeInfo<br>MBeanParameterInfo</td> 105 * 106 * <td>Default value for an attribute or parameter. See 107 * {@link javax.management.openmbean}.</td> 108 * 109 * <tr><td>deprecated</td><td>String</td><td>Any</td> 110 * 111 * <td>An indication that this element of the information model is no 112 * longer recommended for use. A set of MBeans defined by an 113 * application is collectively called an <em>information model</em>. 114 * The convention is for the value of this field to contain a string 115 * that is the version of the model in which the element was first 116 * deprecated, followed by a space, followed by an explanation of the 117 * deprecation, for example {@code "1.3 Replaced by the Capacity 118 * attribute"}.</td> 119 * 120 * <tr><td id="descriptionResourceBundleBaseName">descriptionResource<br> 121 * BundleBaseName</td><td>String</td><td>Any</td> 122 * 123 * <td>The base name for the {@link ResourceBundle} in which the key given in 124 * the {@code descriptionResourceKey} field can be found, for example 125 * {@code "com.example.myapp.MBeanResources"}. The meaning of this 126 * field is defined by this specification but the field is not set or 127 * used by the JMX API itself.</td> 128 * 129 * <tr><td id="descriptionResourceKey">descriptionResourceKey</td> 130 * <td>String</td><td>Any</td> 131 * 132 * <td>A resource key for the description of this element. In 133 * conjunction with the {@code descriptionResourceBundleBaseName}, 134 * this can be used to find a localized version of the description. 135 * The meaning of this field is defined by this specification but the 136 * field is not set or used by the JMX API itself.</td> 137 * 138 * <tr><td>enabled</td><td>String</td> 139 * <td>MBeanAttributeInfo<br>MBeanNotificationInfo<br>MBeanOperationInfo</td> 140 * 141 * <td>The string {@code "true"} or {@code "false"} according as this 142 * item is enabled. When an attribute or operation is not enabled, it 143 * exists but cannot currently be accessed. A user interface might 144 * present it as a greyed-out item. For example, an attribute might 145 * only be meaningful after the {@code start()} method of an MBean has 146 * been called, and is otherwise disabled. Likewise, a notification 147 * might be disabled if it cannot currently be emitted but could be in 148 * other circumstances.</td> 149 * 150 * <tr id="exceptions"><td>exceptions<td>String[]</td> 151 * <td>MBeanAttributeInfo, MBeanConstructorInfo, MBeanOperationInfo</td> 152 * 153 * <td>The class names of the exceptions that can be thrown when invoking a 154 * constructor or operation, or getting an attribute. The meaning of this field 155 * is defined by this specification but the field is not set or used by the 156 * JMX API itself. Exceptions thrown when 157 * setting an attribute are specified by the field 158 * <a href="#setExceptions">{@code setExceptions}</a>. 159 * 160 * <tr id="immutableInfo"><td><i>immutableInfo</i><td>String</td> 161 * <td>MBeanInfo</td> 162 * 163 * <td>The string {@code "true"} or {@code "false"} according as this 164 * MBean's MBeanInfo is <em>immutable</em>. When this field is true, 165 * the MBeanInfo for the given MBean is guaranteed not to change over 166 * the lifetime of the MBean. Hence, a client can read it once and 167 * cache the read value. When this field is false or absent, there is 168 * no such guarantee, although that does not mean that the MBeanInfo 169 * will necessarily change. See also the <a 170 * href="MBeanInfo.html#info-changed">{@code "jmx.mbean.info.changed"}</a> 171 * notification.</td> 172 * 173 * <tr id="infoTimeout"><td>infoTimeout</td><td>String<br>Long</td><td>MBeanInfo</td> 174 * 175 * <td>The time in milli-seconds that the MBeanInfo can reasonably be 176 * expected to be unchanged. The value can be a {@code Long} or a 177 * decimal string. This provides a hint from a DynamicMBean or any 178 * MBean that does not define {@code immutableInfo} as {@code true} 179 * that the MBeanInfo is not likely to change within this period and 180 * therefore can be cached. When this field is missing or has the 181 * value zero, it is not recommended to cache the MBeanInfo unless it 182 * has the {@code immutableInfo} set to {@code true} or it has <a 183 * href="MBeanInfo.html#info-changed">{@code "jmx.mbean.info.changed"}</a> in 184 * its {@link MBeanNotificationInfo} array.</td></tr> 185 * 186 * <tr id="interfaceClassName"><td><i>interfaceClassName</i></td> 187 * <td>String</td><td>MBeanInfo</td> 188 * 189 * <td>The Java interface name for a Standard MBean or MXBean, as 190 * returned by {@link Class#getName()}. A Standard MBean or MXBean 191 * registered directly in the MBean Server or created using the {@link 192 * StandardMBean} class will have this field in its MBeanInfo 193 * Descriptor.</td> 194 * 195 * <tr id="legalValues"><td><i>legalValues</i></td> 196 * <td>{@literal Set<?>}</td><td>MBeanAttributeInfo<br>MBeanParameterInfo</td> 197 * 198 * <td>Legal values for an attribute or parameter. See 199 * {@link javax.management.openmbean}.</td> 200 * 201 * <tr id="locale"><td>locale</td> 202 * <td>String</td><td>Any</td> 203 * 204 * <td>The {@linkplain Locale locale} of the description in this 205 * {@code MBeanInfo}, {@code MBeanAttributeInfo}, etc, as returned 206 * by {@link Locale#toString()}.</td> 207 * 208 * <tr id="maxValue"><td><i>maxValue</i><td>Object</td> 209 * <td>MBeanAttributeInfo<br>MBeanParameterInfo</td> 210 * 211 * <td>Maximum legal value for an attribute or parameter. See 212 * {@link javax.management.openmbean}.</td> 213 * 214 * <tr id="metricType"><td>metricType</td><td>String</td> 215 * <td>MBeanAttributeInfo<br>MBeanOperationInfo</td> 216 * 217 * <td>The type of a metric, one of the strings "counter" or "gauge". 218 * A metric is a measurement exported by an MBean, usually an 219 * attribute but sometimes the result of an operation. A metric that 220 * is a <em>counter</em> has a value that never decreases except by 221 * being reset to a starting value. Counter metrics are almost always 222 * non-negative integers. An example might be the number of requests 223 * received. A metric that is a <em>gauge</em> has a numeric value 224 * that can increase or decrease. Examples might be the number of 225 * open connections or a cache hit rate or a temperature reading. 226 * 227 * <tr id="minValue"><td><i>minValue</i><td>Object</td> 228 * <td>MBeanAttributeInfo<br>MBeanParameterInfo</td> 229 * 230 * <td>Minimum legal value for an attribute or parameter. See 231 * {@link javax.management.openmbean}.</td> 232 * 233 * <tr id="mxbean"><td><i>mxbean</i><td>String</td> 234 * <td>MBeanInfo</td> 235 * 236 * <td>The string {@code "true"} or {@code "false"} according as this 237 * MBean is an {@link MXBean}. A Standard MBean or MXBean registered 238 * directly with the MBean Server or created using the {@link 239 * StandardMBean} class will have this field in its MBeanInfo 240 * Descriptor.</td> 241 * 242 * <tr id="openType"><td><i>openType</i><td>{@link OpenType}</td> 243 * <td>MBeanAttributeInfo<br>MBeanOperationInfo<br>MBeanParameterInfo</td> 244 * 245 * <td><p>The Open Type of this element. In the case of {@code 246 * MBeanAttributeInfo} and {@code MBeanParameterInfo}, this is the 247 * Open Type of the attribute or parameter. In the case of {@code 248 * MBeanOperationInfo}, it is the Open Type of the return value. This 249 * field is set in the Descriptor for all instances of {@link 250 * OpenMBeanAttributeInfoSupport}, {@link 251 * OpenMBeanOperationInfoSupport}, and {@link 252 * OpenMBeanParameterInfoSupport}. It is also set for attributes, 253 * operations, and parameters of MXBeans.</p> 254 * 255 * <p>This field can be set for an {@code MBeanNotificationInfo}, in 256 * which case it indicates the Open Type that the {@link 257 * Notification#getUserData() user data} will have.</td> 258 * 259 * <tr id="originalType"><td><i>originalType</i><td>String</td> 260 * <td>MBeanAttributeInfo<br>MBeanOperationInfo<br>MBeanParameterInfo</td> 261 * 262 * <td><p>The original Java type of this element as it appeared in the 263 * {@link MXBean} interface method that produced this {@code 264 * MBeanAttributeInfo} (etc). For example, a method<br> <code>public 265 * </code> {@link MemoryUsage}<code> getHeapMemoryUsage();</code><br> 266 * in an MXBean interface defines an attribute called {@code 267 * HeapMemoryUsage} of type {@link CompositeData}. The {@code 268 * originalType} field in the Descriptor for this attribute will have 269 * the value {@code "java.lang.management.MemoryUsage"}. 270 * 271 * <p>The format of this string is described in the section <a 272 * href="MXBean.html#type-names">Type Names</a> of the MXBean 273 * specification.</p> 274 * 275 * <tr id="setExceptions"><td><i>setExceptions</i><td>String[]</td> 276 * <td>MBeanAttributeInfo</td> 277 * 278 * <td>The class names of the exceptions that can be thrown when setting 279 * an attribute. The meaning of this field 280 * is defined by this specification but the field is not set or used by the 281 * JMX API itself. Exceptions thrown when getting an attribute are specified 282 * by the field <a href="#exceptions">{@code exceptions}</a>. 283 * 284 * <tr><td>severity</td><td>String<br>Integer</td> 285 * <td>MBeanNotificationInfo</td> 286 * 287 * <td>The severity of this notification. It can be 0 to mean 288 * unknown severity or a value from 1 to 6 representing decreasing 289 * levels of severity. It can be represented as a decimal string or 290 * an {@code Integer}.</td> 291 * 292 * <tr><td>since</td><td>String</td><td>Any</td> 293 * 294 * <td>The version of the information model in which this element 295 * was introduced. A set of MBeans defined by an application is 296 * collectively called an <em>information model</em>. The 297 * application may also define versions of this model, and use the 298 * {@code "since"} field to record the version in which an element 299 * first appeared.</td> 300 * 301 * <tr><td>units</td><td>String</td> 302 * <td>MBeanAttributeInfo<br>MBeanParameterInfo<br>MBeanOperationInfo</td> 303 * 304 * <td>The units in which an attribute, parameter, or operation return 305 * value is measured, for example {@code "bytes"} or {@code 306 * "seconds"}.</td> 307 * 308 * </table> 309 * 310 * <p>Some additional fields are defined by Model MBeans. See the 311 * information for <a href="modelmbean/ModelMBeanInfo.html#descriptor"><!-- 312 * -->{@code ModelMBeanInfo}</a>, 313 * <a href="modelmbean/ModelMBeanAttributeInfo.html#descriptor"><!-- 314 * -->{@code ModelMBeanAttributeInfo}</a>, 315 * <a href="modelmbean/ModelMBeanConstructorInfo.html#descriptor"><!-- 316 * -->{@code ModelMBeanConstructorInfo}</a>, 317 * <a href="modelmbean/ModelMBeanNotificationInfo.html#descriptor"><!-- 318 * -->{@code ModelMBeanNotificationInfo}</a>, and 319 * <a href="modelmbean/ModelMBeanOperationInfo.html#descriptor"><!-- 320 * -->{@code ModelMBeanOperationInfo}</a>, as 321 * well as the chapter "Model MBeans" of the <a 322 * href="http://www.oracle.com/technetwork/java/javase/tech/javamanagement-140525.html">JMX 323 * Specification</a>. The following table summarizes these fields. Note 324 * that when the Type in this table is Number, a String that is the decimal 325 * representation of a Long can also be used.</p> 326 * 327 * <p>Nothing prevents the use of these fields in MBeans that are not Model 328 * MBeans. The <a href="#displayName">displayName</a>, <a href="#severity"><!-- 329 * -->severity</a>, and <a href="#visibility">visibility</a> fields are of 330 * interest outside Model MBeans, for example. But only Model MBeans have 331 * a predefined behavior for these fields.</p> 332 * 333 * <table border="1" cellpadding="5"> 334 * 335 * <tr><th>Name</th><th>Type</th><th>Used in</th><th>Meaning</th></tr> 336 * 337 * <tr><td>class</td><td>String</td><td>ModelMBeanOperationInfo</td> 338 * <td>Class where method is defined (fully qualified).</td></tr> 339 * 340 * <tr><td>currencyTimeLimit</td><td>Number</td> 341 * <td>ModelMBeanInfo<br>ModelMBeanAttributeInfo<br>ModelMBeanOperationInfo</td> 342 * <td>How long cached value is valid: <0 never, =0 always, 343 * >0 seconds.</td></tr> 344 * 345 * <tr><td>default</td><td>Object</td><td>ModelMBeanAttributeInfo</td> 346 * <td>Default value for attribute.</td></tr> 347 * 348 * <tr><td>descriptorType</td><td>String</td><td>Any</td> 349 * <td>Type of descriptor, "mbean", "attribute", "constructor", "operation", 350 * or "notification".</td></tr> 351 * 352 * <tr id="displayName"><td>displayName</td><td>String</td><td>Any</td> 353 * <td>Human readable name of this item.</td></tr> 354 * 355 * <tr><td>export</td><td>String</td><td>ModelMBeanInfo</td> 356 * <td>Name to be used to export/expose this MBean so that it is 357 * findable by other JMX Agents.</td></tr> 358 * 359 * <tr><td>getMethod</td><td>String</td><td>ModelMBeanAttributeInfo</td> 360 * <td>Name of operation descriptor for get method.</td></tr> 361 * 362 * <tr><td>lastUpdatedTimeStamp</td><td>Number</td> 363 * <td>ModelMBeanAttributeInfo<br>ModelMBeanOperationInfo</td> 364 * <td>When <a href="#value-field">value</a> was set.</td></tr> 365 * 366 * <tr><td>log</td><td>String</td><td>ModelMBeanInfo<br>ModelMBeanNotificationInfo</td> 367 * <td>t or T: log all notifications, f or F: log no notifications.</td></tr> 368 * 369 * <tr><td>logFile</td><td>String</td><td>ModelMBeanInfo<br>ModelMBeanNotificationInfo</td> 370 * <td>Fully qualified filename to log events to.</td></tr> 371 * 372 * <tr><td>messageID</td><td>String</td><td>ModelMBeanNotificationInfo</td> 373 * <td>Unique key for message text (to allow translation, analysis).</td></tr> 374 * 375 * <tr><td>messageText</td><td>String</td><td>ModelMBeanNotificationInfo</td> 376 * <td>Text of notification.</td></tr> 377 * 378 * <tr><td>name</td><td>String</td><td>Any</td> 379 * <td>Name of this item.</td></tr> 380 * 381 * <tr><td>persistFile</td><td>String</td><td>ModelMBeanInfo</td> 382 * <td>File name into which the MBean should be persisted.</td></tr> 383 * 384 * <tr><td>persistLocation</td><td>String</td><td>ModelMBeanInfo</td> 385 * <td>The fully qualified directory name where the MBean should be 386 * persisted (if appropriate).</td></tr> 387 * 388 * <tr><td>persistPeriod</td><td>Number</td> 389 * <td>ModelMBeanInfo<br>ModelMBeanAttributeInfo</td> 390 * <td>Frequency of persist cycle in seconds. Used when persistPolicy is 391 * "OnTimer" or "NoMoreOftenThan".</td></tr> 392 * 393 * <tr><td>persistPolicy</td><td>String</td> 394 * <td>ModelMBeanInfo<br>ModelMBeanAttributeInfo</td> 395 * <td>One of: OnUpdate|OnTimer|NoMoreOftenThan|OnUnregister|Always|Never. 396 * See the section "MBean Descriptor Fields" in the JMX specification 397 * document.</td></tr> 398 * 399 * <tr><td>presentationString</td><td>String</td><td>Any</td> 400 * <td>XML formatted string to allow presentation of data.</td></tr> 401 * 402 * <tr><td>protocolMap</td><td>Descriptor</td><td>ModelMBeanAttributeInfo</td> 403 * <td>See the section "Protocol Map Support" in the JMX specification 404 * document. Mappings must be appropriate for the attribute and entries 405 * can be updated or augmented at runtime.</td></tr> 406 * 407 * <tr><td>role</td><td>String</td> 408 * <td>ModelMBeanConstructorInfo<br>ModelMBeanOperationInfo</td> 409 * <td>One of "constructor", "operation", "getter", or "setter".</td></tr> 410 * 411 * <tr><td>setMethod</td><td>String</td><td>ModelMBeanAttributeInfo</td> 412 * <td>Name of operation descriptor for set method.</td></tr> 413 * 414 * <tr id="severity"><td>severity</td><td>Number</td> 415 * <td>ModelMBeanNotificationInfo</td> 416 * <td>0-6 where 0: unknown; 1: non-recoverable; 417 * 2: critical, failure; 3: major, severe; 418 * 4: minor, marginal, error; 5: warning; 419 * 6: normal, cleared, informative</td></tr> 420 * 421 * <tr><td>targetObject</td><td>Object</td><td>ModelMBeanOperationInfo</td> 422 * <td>Object on which to execute this method.</td></tr> 423 * 424 * <tr><td>targetType</td><td>String</td><td>ModelMBeanOperationInfo</td> 425 * <td>type of object reference for targetObject. Can be: 426 * ObjectReference | Handle | EJBHandle | IOR | RMIReference.</td></tr> 427 * 428 * <tr id="value-field"><td>value</td><td>Object</td> 429 * <td>ModelMBeanAttributeInfo<br>ModelMBeanOperationInfo</td> 430 * <td>Current (cached) value for attribute or operation.</td></tr> 431 * 432 * <tr id="visibility"><td>visibility</td><td>Number</td><td>Any</td> 433 * <td>1-4 where 1: always visible, 4: rarely visible.</td></tr> 434 * 435 * </table> 436 * 437 * @since 1.5 438 */ 439 public interface Descriptor extends Serializable, Cloneable 440 { 441 442 /** 443 * Returns the value for a specific field name, or null if no value 444 * is present for that name. 445 * 446 * @param fieldName the field name. 447 * 448 * @return the corresponding value, or null if the field is not present. 449 * 450 * @exception RuntimeOperationsException if the field name is illegal. 451 */ 452 public Object getFieldValue(String fieldName) 453 throws RuntimeOperationsException; 454 455 /** 456 * <p>Sets the value for a specific field name. This will 457 * modify an existing field or add a new field.</p> 458 * 459 * <p>The field value will be validated before it is set. 460 * If it is not valid, then an exception will be thrown. 461 * The meaning of validity is dependent on the descriptor 462 * implementation.</p> 463 * 464 * @param fieldName The field name to be set. Cannot be null or empty. 465 * @param fieldValue The field value to be set for the field 466 * name. Can be null if that is a valid value for the field. 467 * 468 * @exception RuntimeOperationsException if the field name or field value 469 * is illegal (wrapped exception is {@link IllegalArgumentException}); or 470 * if the descriptor is immutable (wrapped exception is 471 * {@link UnsupportedOperationException}). 472 */ 473 public void setField(String fieldName, Object fieldValue) 474 throws RuntimeOperationsException; 475 476 477 /** 478 * Returns all of the fields contained in this descriptor as a string array. 479 * 480 * @return String array of fields in the format <i>fieldName=fieldValue</i> 481 * <br>If the value of a field is not a String, then the toString() method 482 * will be called on it and the returned value, enclosed in parentheses, 483 * used as the value for the field in the returned array. If the value 484 * of a field is null, then the value of the field in the returned array 485 * will be empty. If the descriptor is empty, you will get 486 * an empty array. 487 * 488 * @see #setFields 489 */ 490 public String[] getFields(); 491 492 493 /** 494 * Returns all the field names in the descriptor. 495 * 496 * @return String array of field names. If the descriptor is empty, 497 * you will get an empty array. 498 */ 499 public String[] getFieldNames(); 500 501 /** 502 * Returns all the field values in the descriptor as an array of Objects. The 503 * returned values are in the same order as the {@code fieldNames} String array parameter. 504 * 505 * @param fieldNames String array of the names of the fields that 506 * the values should be returned for. If the array is empty then 507 * an empty array will be returned. If the array is null then all 508 * values will be returned, as if the parameter were the array 509 * returned by {@link #getFieldNames()}. If a field name in the 510 * array does not exist, including the case where it is null or 511 * the empty string, then null is returned for the matching array 512 * element being returned. 513 * 514 * @return Object array of field values. If the list of {@code fieldNames} 515 * is empty, you will get an empty array. 516 */ 517 public Object[] getFieldValues(String... fieldNames); 518 519 /** 520 * Removes a field from the descriptor. 521 * 522 * @param fieldName String name of the field to be removed. 523 * If the field name is illegal or the field is not found, 524 * no exception is thrown. 525 * 526 * @exception RuntimeOperationsException if a field of the given name 527 * exists and the descriptor is immutable. The wrapped exception will 528 * be an {@link UnsupportedOperationException}. 529 */ 530 public void removeField(String fieldName); 531 532 /** 533 * <p>Sets all fields in the field names array to the new value with 534 * the same index in the field values array. Array sizes must match.</p> 535 * 536 * <p>The field value will be validated before it is set. 537 * If it is not valid, then an exception will be thrown. 538 * If the arrays are empty, then no change will take effect.</p> 539 * 540 * @param fieldNames String array of field names. The array and array 541 * elements cannot be null. 542 * @param fieldValues Object array of the corresponding field values. 543 * The array cannot be null. Elements of the array can be null. 544 * 545 * @throws RuntimeOperationsException if the change fails for any reason. 546 * Wrapped exception is {@link IllegalArgumentException} if 547 * {@code fieldNames} or {@code fieldValues} is null, or if 548 * the arrays are of different lengths, or if there is an 549 * illegal value in one of them. 550 * Wrapped exception is {@link UnsupportedOperationException} 551 * if the descriptor is immutable, and the call would change 552 * its contents. 553 * 554 * @see #getFields 555 */ 556 public void setFields(String[] fieldNames, Object[] fieldValues) 557 throws RuntimeOperationsException; 558 559 560 /** 561 * <p>Returns a descriptor which is equal to this descriptor. 562 * Changes to the returned descriptor will have no effect on this 563 * descriptor, and vice versa. If this descriptor is immutable, 564 * it may fulfill this condition by returning itself.</p> 565 * @exception RuntimeOperationsException for illegal value for field names 566 * or field values. 567 * If the descriptor construction fails for any reason, this exception will 568 * be thrown. 569 * @return A descriptor which is equal to this descriptor. 570 */ 571 public Object clone() throws RuntimeOperationsException; 572 573 574 /** 575 * Returns true if all of the fields have legal values given their 576 * names. 577 * 578 * @return true if the values are legal. 579 * 580 * @exception RuntimeOperationsException If the validity checking fails for 581 * any reason, this exception will be thrown. 582 * The method returns false if the descriptor is not valid, but throws 583 * this exception if the attempt to determine validity fails. 584 */ 585 public boolean isValid() throws RuntimeOperationsException; 586 587 /** 588 * <p>Compares this descriptor to the given object. The objects are equal if 589 * the given object is also a Descriptor, and if the two Descriptors have 590 * the same field names (possibly differing in case) and the same 591 * associated values. The respective values for a field in the two 592 * Descriptors are equal if the following conditions hold:</p> 593 * 594 * <ul> 595 * <li>If one value is null then the other must be too.</li> 596 * <li>If one value is a primitive array then the other must be a primitive 597 * array of the same type with the same elements.</li> 598 * <li>If one value is an object array then the other must be too and 599 * {@link Arrays#deepEquals(Object[],Object[])} must return true.</li> 600 * <li>Otherwise {@link Object#equals(Object)} must return true.</li> 601 * </ul> 602 * 603 * @param obj the object to compare with. 604 * 605 * @return {@code true} if the objects are the same; {@code false} 606 * otherwise. 607 * 608 * @since 1.6 609 */ 610 public boolean equals(Object obj); 611 612 /** 613 * <p>Returns the hash code value for this descriptor. The hash 614 * code is computed as the sum of the hash codes for each field in 615 * the descriptor. The hash code of a field with name {@code n} 616 * and value {@code v} is {@code n.toLowerCase().hashCode() ^ h}. 617 * Here {@code h} is the hash code of {@code v}, computed as 618 * follows:</p> 619 * 620 * <ul> 621 * <li>If {@code v} is null then {@code h} is 0.</li> 622 * <li>If {@code v} is a primitive array then {@code h} is computed using 623 * the appropriate overloading of {@code java.util.Arrays.hashCode}.</li> 624 * <li>If {@code v} is an object array then {@code h} is computed using 625 * {@link Arrays#deepHashCode(Object[])}.</li> 626 * <li>Otherwise {@code h} is {@code v.hashCode()}.</li> 627 * </ul> 628 * 629 * @return A hash code value for this object. 630 * 631 * @since 1.6 632 */ 633 public int hashCode(); 634 }