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| 1 | /* | ||
| 2 | * Copyright (c) 1994, 2010, 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 java.lang; | ||
| 27 | |||
| 28 | /** | ||
| 29 | * Class {@code Object} is the root of the class hierarchy. | ||
| 30 | * Every class has {@code Object} as a superclass. All objects, | ||
| 31 | * including arrays, implement the methods of this class. | ||
| 32 | * | ||
| 33 | * @author unascribed | ||
| 34 | * @see java.lang.Class | ||
| 35 | * @since JDK1.0 | ||
| 36 | */ | ||
| 37 | public class Object { | ||
| 38 | |||
| 39 | private static native void registerNatives(); | ||
| 40 | static { | ||
| 41 | registerNatives(); | ||
| 42 | } | ||
| 43 | |||
| 44 | /** | ||
| 45 | * Returns the runtime class of this {@code Object}. The returned | ||
| 46 | * {@code Class} object is the object that is locked by {@code | ||
| 47 | * static synchronized} methods of the represented class. | ||
| 48 | * | ||
| 49 | * <p><b>The actual result type is {@code Class<? extends |X|>} | ||
| 50 | * where {@code |X|} is the erasure of the static type of the | ||
| 51 | * expression on which {@code getClass} is called.</b> For | ||
| 52 | * example, no cast is required in this code fragment:</p> | ||
| 53 | * | ||
| 54 | * <p> | ||
| 55 | * {@code Number n = 0; }<br> | ||
| 56 | * {@code Class<? extends Number> c = n.getClass(); } | ||
| 57 | * </p> | ||
| 58 | * | ||
| 59 | * @return The {@code Class} object that represents the runtime | ||
| 60 | * class of this object. | ||
| 61 | * @see Class Literals, section 15.8.2 of | ||
| 62 | * <cite>The Java™ Language Specification</cite>. | ||
| 63 | */ | ||
| 64 | public final native Class<?> getClass(); | ||
| 65 | |||
| 66 | /** | ||
| 67 | * Returns a hash code value for the object. This method is | ||
| 68 | * supported for the benefit of hash tables such as those provided by | ||
| 69 | * {@link java.util.HashMap}. | ||
| 70 | * <p> | ||
| 71 | * The general contract of {@code hashCode} is: | ||
| 72 | * <ul> | ||
| 73 | * <li>Whenever it is invoked on the same object more than once during | ||
| 74 | * an execution of a Java application, the {@code hashCode} method | ||
| 75 | * must consistently return the same integer, provided no information | ||
| 76 | * used in {@code equals} comparisons on the object is modified. | ||
| 77 | * This integer need not remain consistent from one execution of an | ||
| 78 | * application to another execution of the same application. | ||
| 79 | * <li>If two objects are equal according to the {@code equals(Object)} | ||
| 80 | * method, then calling the {@code hashCode} method on each of | ||
| 81 | * the two objects must produce the same integer result. | ||
| 82 | * <li>It is <em>not</em> required that if two objects are unequal | ||
| 83 | * according to the {@link java.lang.Object#equals(java.lang.Object)} | ||
| 84 | * method, then calling the {@code hashCode} method on each of the | ||
| 85 | * two objects must produce distinct integer results. However, the | ||
| 86 | * programmer should be aware that producing distinct integer results | ||
| 87 | * for unequal objects may improve the performance of hash tables. | ||
| 88 | * </ul> | ||
| 89 | * <p> | ||
| 90 | * As much as is reasonably practical, the hashCode method defined by | ||
| 91 | * class {@code Object} does return distinct integers for distinct | ||
| 92 | * objects. (This is typically implemented by converting the internal | ||
| 93 | * address of the object into an integer, but this implementation | ||
| 94 | * technique is not required by the | ||
| 95 | * Java<font size="-2"><sup>TM</sup></font> programming language.) | ||
| 96 | * | ||
| 97 | * @return a hash code value for this object. | ||
| 98 | * @see java.lang.Object#equals(java.lang.Object) | ||
| 99 | * @see java.lang.System#identityHashCode | ||
| 100 | */ | ||
| 101 | public native int hashCode(); | ||
| 102 | |||
| 103 | /** | ||
| 104 | * Indicates whether some other object is "equal to" this one. | ||
| 105 | * <p> | ||
| 106 | * The {@code equals} method implements an equivalence relation | ||
| 107 | * on non-null object references: | ||
| 108 | * <ul> | ||
| 109 | * <li>It is <i>reflexive</i>: for any non-null reference value | ||
| 110 | * {@code x}, {@code x.equals(x)} should return | ||
| 111 | * {@code true}. | ||
| 112 | * <li>It is <i>symmetric</i>: for any non-null reference values | ||
| 113 | * {@code x} and {@code y}, {@code x.equals(y)} | ||
| 114 | * should return {@code true} if and only if | ||
| 115 | * {@code y.equals(x)} returns {@code true}. | ||
| 116 | * <li>It is <i>transitive</i>: for any non-null reference values | ||
| 117 | * {@code x}, {@code y}, and {@code z}, if | ||
| 118 | * {@code x.equals(y)} returns {@code true} and | ||
| 119 | * {@code y.equals(z)} returns {@code true}, then | ||
| 120 | * {@code x.equals(z)} should return {@code true}. | ||
| 121 | * <li>It is <i>consistent</i>: for any non-null reference values | ||
| 122 | * {@code x} and {@code y}, multiple invocations of | ||
| 123 | * {@code x.equals(y)} consistently return {@code true} | ||
| 124 | * or consistently return {@code false}, provided no | ||
| 125 | * information used in {@code equals} comparisons on the | ||
| 126 | * objects is modified. | ||
| 127 | * <li>For any non-null reference value {@code x}, | ||
| 128 | * {@code x.equals(null)} should return {@code false}. | ||
| 129 | * </ul> | ||
| 130 | * <p> | ||
| 131 | * The {@code equals} method for class {@code Object} implements | ||
| 132 | * the most discriminating possible equivalence relation on objects; | ||
| 133 | * that is, for any non-null reference values {@code x} and | ||
| 134 | * {@code y}, this method returns {@code true} if and only | ||
| 135 | * if {@code x} and {@code y} refer to the same object | ||
| 136 | * ({@code x == y} has the value {@code true}). | ||
| 137 | * <p> | ||
| 138 | * Note that it is generally necessary to override the {@code hashCode} | ||
| 139 | * method whenever this method is overridden, so as to maintain the | ||
| 140 | * general contract for the {@code hashCode} method, which states | ||
| 141 | * that equal objects must have equal hash codes. | ||
| 142 | * | ||
| 143 | * @param obj the reference object with which to compare. | ||
| 144 | * @return {@code true} if this object is the same as the obj | ||
| 145 | * argument; {@code false} otherwise. | ||
| 146 | * @see #hashCode() | ||
| 147 | * @see java.util.HashMap | ||
| 148 | */ | ||
| 149 | public boolean equals(Object obj) { | ||
| 150 | return (this == obj); | ||
| 151 | } | ||
| 152 | |||
| 153 | /** | ||
| 154 | * Creates and returns a copy of this object. The precise meaning | ||
| 155 | * of "copy" may depend on the class of the object. The general | ||
| 156 | * intent is that, for any object {@code x}, the expression: | ||
| 157 | * <blockquote> | ||
| 158 | * <pre> | ||
| 159 | * x.clone() != x</pre></blockquote> | ||
| 160 | * will be true, and that the expression: | ||
| 161 | * <blockquote> | ||
| 162 | * <pre> | ||
| 163 | * x.clone().getClass() == x.getClass()</pre></blockquote> | ||
| 164 | * will be {@code true}, but these are not absolute requirements. | ||
| 165 | * While it is typically the case that: | ||
| 166 | * <blockquote> | ||
| 167 | * <pre> | ||
| 168 | * x.clone().equals(x)</pre></blockquote> | ||
| 169 | * will be {@code true}, this is not an absolute requirement. | ||
| 170 | * <p> | ||
| 171 | * By convention, the returned object should be obtained by calling | ||
| 172 | * {@code super.clone}. If a class and all of its superclasses (except | ||
| 173 | * {@code Object}) obey this convention, it will be the case that | ||
| 174 | * {@code x.clone().getClass() == x.getClass()}. | ||
| 175 | * <p> | ||
| 176 | * By convention, the object returned by this method should be independent | ||
| 177 | * of this object (which is being cloned). To achieve this independence, | ||
| 178 | * it may be necessary to modify one or more fields of the object returned | ||
| 179 | * by {@code super.clone} before returning it. Typically, this means | ||
| 180 | * copying any mutable objects that comprise the internal "deep structure" | ||
| 181 | * of the object being cloned and replacing the references to these | ||
| 182 | * objects with references to the copies. If a class contains only | ||
| 183 | * primitive fields or references to immutable objects, then it is usually | ||
| 184 | * the case that no fields in the object returned by {@code super.clone} | ||
| 185 | * need to be modified. | ||
| 186 | * <p> | ||
| 187 | * The method {@code clone} for class {@code Object} performs a | ||
| 188 | * specific cloning operation. First, if the class of this object does | ||
| 189 | * not implement the interface {@code Cloneable}, then a | ||
| 190 | * {@code CloneNotSupportedException} is thrown. Note that all arrays | ||
| 191 | * are considered to implement the interface {@code Cloneable} and that | ||
| 192 | * the return type of the {@code clone} method of an array type {@code T[]} | ||
| 193 | * is {@code T[]} where T is any reference or primitive type. | ||
| 194 | * Otherwise, this method creates a new instance of the class of this | ||
| 195 | * object and initializes all its fields with exactly the contents of | ||
| 196 | * the corresponding fields of this object, as if by assignment; the | ||
| 197 | * contents of the fields are not themselves cloned. Thus, this method | ||
| 198 | * performs a "shallow copy" of this object, not a "deep copy" operation. | ||
| 199 | * <p> | ||
| 200 | * The class {@code Object} does not itself implement the interface | ||
| 201 | * {@code Cloneable}, so calling the {@code clone} method on an object | ||
| 202 | * whose class is {@code Object} will result in throwing an | ||
| 203 | * exception at run time. | ||
| 204 | * | ||
| 205 | * @return a clone of this instance. | ||
| 206 | * @exception CloneNotSupportedException if the object's class does not | ||
| 207 | * support the {@code Cloneable} interface. Subclasses | ||
| 208 | * that override the {@code clone} method can also | ||
| 209 | * throw this exception to indicate that an instance cannot | ||
| 210 | * be cloned. | ||
| 211 | * @see java.lang.Cloneable | ||
| 212 | */ | ||
| 213 | protected native Object clone() throws CloneNotSupportedException; | ||
| 214 | |||
| 215 | /** | ||
| 216 | * Returns a string representation of the object. In general, the | ||
| 217 | * {@code toString} method returns a string that | ||
| 218 | * "textually represents" this object. The result should | ||
| 219 | * be a concise but informative representation that is easy for a | ||
| 220 | * person to read. | ||
| 221 | * It is recommended that all subclasses override this method. | ||
| 222 | * <p> | ||
| 223 | * The {@code toString} method for class {@code Object} | ||
| 224 | * returns a string consisting of the name of the class of which the | ||
| 225 | * object is an instance, the at-sign character `{@code @}', and | ||
| 226 | * the unsigned hexadecimal representation of the hash code of the | ||
| 227 | * object. In other words, this method returns a string equal to the | ||
| 228 | * value of: | ||
| 229 | * <blockquote> | ||
| 230 | * <pre> | ||
| 231 | * getClass().getName() + '@' + Integer.toHexString(hashCode()) | ||
| 232 | * </pre></blockquote> | ||
| 233 | * | ||
| 234 | * @return a string representation of the object. | ||
| 235 | */ | ||
| 236 | public String toString() { | ||
| 237 | return getClass().getName() + "@" + Integer.toHexString(hashCode()); | ||
| 238 | } | ||
| 239 | |||
| 240 | /** | ||
| 241 | * Wakes up a single thread that is waiting on this object's | ||
| 242 | * monitor. If any threads are waiting on this object, one of them | ||
| 243 | * is chosen to be awakened. The choice is arbitrary and occurs at | ||
| 244 | * the discretion of the implementation. A thread waits on an object's | ||
| 245 | * monitor by calling one of the {@code wait} methods. | ||
| 246 | * <p> | ||
| 247 | * The awakened thread will not be able to proceed until the current | ||
| 248 | * thread relinquishes the lock on this object. The awakened thread will | ||
| 249 | * compete in the usual manner with any other threads that might be | ||
| 250 | * actively competing to synchronize on this object; for example, the | ||
| 251 | * awakened thread enjoys no reliable privilege or disadvantage in being | ||
| 252 | * the next thread to lock this object. | ||
| 253 | * <p> | ||
| 254 | * This method should only be called by a thread that is the owner | ||
| 255 | * of this object's monitor. A thread becomes the owner of the | ||
| 256 | * object's monitor in one of three ways: | ||
| 257 | * <ul> | ||
| 258 | * <li>By executing a synchronized instance method of that object. | ||
| 259 | * <li>By executing the body of a {@code synchronized} statement | ||
| 260 | * that synchronizes on the object. | ||
| 261 | * <li>For objects of type {@code Class,} by executing a | ||
| 262 | * synchronized static method of that class. | ||
| 263 | * </ul> | ||
| 264 | * <p> | ||
| 265 | * Only one thread at a time can own an object's monitor. | ||
| 266 | * | ||
| 267 | * @exception IllegalMonitorStateException if the current thread is not | ||
| 268 | * the owner of this object's monitor. | ||
| 269 | * @see java.lang.Object#notifyAll() | ||
| 270 | * @see java.lang.Object#wait() | ||
| 271 | */ | ||
| 272 | public final native void notify(); | ||
| 273 | |||
| 274 | /** | ||
| 275 | * Wakes up all threads that are waiting on this object's monitor. A | ||
| 276 | * thread waits on an object's monitor by calling one of the | ||
| 277 | * {@code wait} methods. | ||
| 278 | * <p> | ||
| 279 | * The awakened threads will not be able to proceed until the current | ||
| 280 | * thread relinquishes the lock on this object. The awakened threads | ||
| 281 | * will compete in the usual manner with any other threads that might | ||
| 282 | * be actively competing to synchronize on this object; for example, | ||
| 283 | * the awakened threads enjoy no reliable privilege or disadvantage in | ||
| 284 | * being the next thread to lock this object. | ||
| 285 | * <p> | ||
| 286 | * This method should only be called by a thread that is the owner | ||
| 287 | * of this object's monitor. See the {@code notify} method for a | ||
| 288 | * description of the ways in which a thread can become the owner of | ||
| 289 | * a monitor. | ||
| 290 | * | ||
| 291 | * @exception IllegalMonitorStateException if the current thread is not | ||
| 292 | * the owner of this object's monitor. | ||
| 293 | * @see java.lang.Object#notify() | ||
| 294 | * @see java.lang.Object#wait() | ||
| 295 | */ | ||
| 296 | public final native void notifyAll(); | ||
| 297 | |||
| 298 | /** | ||
| 299 | * Causes the current thread to wait until either another thread invokes the | ||
| 300 | * {@link java.lang.Object#notify()} method or the | ||
| 301 | * {@link java.lang.Object#notifyAll()} method for this object, or a | ||
| 302 | * specified amount of time has elapsed. | ||
| 303 | * <p> | ||
| 304 | * The current thread must own this object's monitor. | ||
| 305 | * <p> | ||
| 306 | * This method causes the current thread (call it <var>T</var>) to | ||
| 307 | * place itself in the wait set for this object and then to relinquish | ||
| 308 | * any and all synchronization claims on this object. Thread <var>T</var> | ||
| 309 | * becomes disabled for thread scheduling purposes and lies dormant | ||
| 310 | * until one of four things happens: | ||
| 311 | * <ul> | ||
| 312 | * <li>Some other thread invokes the {@code notify} method for this | ||
| 313 | * object and thread <var>T</var> happens to be arbitrarily chosen as | ||
| 314 | * the thread to be awakened. | ||
| 315 | * <li>Some other thread invokes the {@code notifyAll} method for this | ||
| 316 | * object. | ||
| 317 | * <li>Some other thread {@linkplain Thread#interrupt() interrupts} | ||
| 318 | * thread <var>T</var>. | ||
| 319 | * <li>The specified amount of real time has elapsed, more or less. If | ||
| 320 | * {@code timeout} is zero, however, then real time is not taken into | ||
| 321 | * consideration and the thread simply waits until notified. | ||
| 322 | * </ul> | ||
| 323 | * The thread <var>T</var> is then removed from the wait set for this | ||
| 324 | * object and re-enabled for thread scheduling. It then competes in the | ||
| 325 | * usual manner with other threads for the right to synchronize on the | ||
| 326 | * object; once it has gained control of the object, all its | ||
| 327 | * synchronization claims on the object are restored to the status quo | ||
| 328 | * ante - that is, to the situation as of the time that the {@code wait} | ||
| 329 | * method was invoked. Thread <var>T</var> then returns from the | ||
| 330 | * invocation of the {@code wait} method. Thus, on return from the | ||
| 331 | * {@code wait} method, the synchronization state of the object and of | ||
| 332 | * thread {@code T} is exactly as it was when the {@code wait} method | ||
| 333 | * was invoked. | ||
| 334 | * <p> | ||
| 335 | * A thread can also wake up without being notified, interrupted, or | ||
| 336 | * timing out, a so-called <i>spurious wakeup</i>. While this will rarely | ||
| 337 | * occur in practice, applications must guard against it by testing for | ||
| 338 | * the condition that should have caused the thread to be awakened, and | ||
| 339 | * continuing to wait if the condition is not satisfied. In other words, | ||
| 340 | * waits should always occur in loops, like this one: | ||
| 341 | * <pre> | ||
| 342 | * synchronized (obj) { | ||
| 343 | * while (<condition does not hold>) | ||
| 344 | * obj.wait(timeout); | ||
| 345 | * ... // Perform action appropriate to condition | ||
| 346 | * } | ||
| 347 | * </pre> | ||
| 348 | * (For more information on this topic, see Section 3.2.3 in Doug Lea's | ||
| 349 | * "Concurrent Programming in Java (Second Edition)" (Addison-Wesley, | ||
| 350 | * 2000), or Item 50 in Joshua Bloch's "Effective Java Programming | ||
| 351 | * Language Guide" (Addison-Wesley, 2001). | ||
| 352 | * | ||
| 353 | * <p>If the current thread is {@linkplain java.lang.Thread#interrupt() | ||
| 354 | * interrupted} by any thread before or while it is waiting, then an | ||
| 355 | * {@code InterruptedException} is thrown. This exception is not | ||
| 356 | * thrown until the lock status of this object has been restored as | ||
| 357 | * described above. | ||
| 358 | * | ||
| 359 | * <p> | ||
| 360 | * Note that the {@code wait} method, as it places the current thread | ||
| 361 | * into the wait set for this object, unlocks only this object; any | ||
| 362 | * other objects on which the current thread may be synchronized remain | ||
| 363 | * locked while the thread waits. | ||
| 364 | * <p> | ||
| 365 | * This method should only be called by a thread that is the owner | ||
| 366 | * of this object's monitor. See the {@code notify} method for a | ||
| 367 | * description of the ways in which a thread can become the owner of | ||
| 368 | * a monitor. | ||
| 369 | * | ||
| 370 | * @param timeout the maximum time to wait in milliseconds. | ||
| 371 | * @exception IllegalArgumentException if the value of timeout is | ||
| 372 | * negative. | ||
| 373 | * @exception IllegalMonitorStateException if the current thread is not | ||
| 374 | * the owner of the object's monitor. | ||
| 375 | * @exception InterruptedException if any thread interrupted the | ||
| 376 | * current thread before or while the current thread | ||
| 377 | * was waiting for a notification. The <i>interrupted | ||
| 378 | * status</i> of the current thread is cleared when | ||
| 379 | * this exception is thrown. | ||
| 380 | * @see java.lang.Object#notify() | ||
| 381 | * @see java.lang.Object#notifyAll() | ||
| 382 | */ | ||
| 383 | public final native void wait(long timeout) throws InterruptedException; | ||
| 384 | |||
| 385 | /** | ||
| 386 | * Causes the current thread to wait until another thread invokes the | ||
| 387 | * {@link java.lang.Object#notify()} method or the | ||
| 388 | * {@link java.lang.Object#notifyAll()} method for this object, or | ||
| 389 | * some other thread interrupts the current thread, or a certain | ||
| 390 | * amount of real time has elapsed. | ||
| 391 | * <p> | ||
| 392 | * This method is similar to the {@code wait} method of one | ||
| 393 | * argument, but it allows finer control over the amount of time to | ||
| 394 | * wait for a notification before giving up. The amount of real time, | ||
| 395 | * measured in nanoseconds, is given by: | ||
| 396 | * <blockquote> | ||
| 397 | * <pre> | ||
| 398 | * 1000000*timeout+nanos</pre></blockquote> | ||
| 399 | * <p> | ||
| 400 | * In all other respects, this method does the same thing as the | ||
| 401 | * method {@link #wait(long)} of one argument. In particular, | ||
| 402 | * {@code wait(0, 0)} means the same thing as {@code wait(0)}. | ||
| 403 | * <p> | ||
| 404 | * The current thread must own this object's monitor. The thread | ||
| 405 | * releases ownership of this monitor and waits until either of the | ||
| 406 | * following two conditions has occurred: | ||
| 407 | * <ul> | ||
| 408 | * <li>Another thread notifies threads waiting on this object's monitor | ||
| 409 | * to wake up either through a call to the {@code notify} method | ||
| 410 | * or the {@code notifyAll} method. | ||
| 411 | * <li>The timeout period, specified by {@code timeout} | ||
| 412 | * milliseconds plus {@code nanos} nanoseconds arguments, has | ||
| 413 | * elapsed. | ||
| 414 | * </ul> | ||
| 415 | * <p> | ||
| 416 | * The thread then waits until it can re-obtain ownership of the | ||
| 417 | * monitor and resumes execution. | ||
| 418 | * <p> | ||
| 419 | * As in the one argument version, interrupts and spurious wakeups are | ||
| 420 | * possible, and this method should always be used in a loop: | ||
| 421 | * <pre> | ||
| 422 | * synchronized (obj) { | ||
| 423 | * while (<condition does not hold>) | ||
| 424 | * obj.wait(timeout, nanos); | ||
| 425 | * ... // Perform action appropriate to condition | ||
| 426 | * } | ||
| 427 | * </pre> | ||
| 428 | * This method should only be called by a thread that is the owner | ||
| 429 | * of this object's monitor. See the {@code notify} method for a | ||
| 430 | * description of the ways in which a thread can become the owner of | ||
| 431 | * a monitor. | ||
| 432 | * | ||
| 433 | * @param timeout the maximum time to wait in milliseconds. | ||
| 434 | * @param nanos additional time, in nanoseconds range | ||
| 435 | * 0-999999. | ||
| 436 | * @exception IllegalArgumentException if the value of timeout is | ||
| 437 | * negative or the value of nanos is | ||
| 438 | * not in the range 0-999999. | ||
| 439 | * @exception IllegalMonitorStateException if the current thread is not | ||
| 440 | * the owner of this object's monitor. | ||
| 441 | * @exception InterruptedException if any thread interrupted the | ||
| 442 | * current thread before or while the current thread | ||
| 443 | * was waiting for a notification. The <i>interrupted | ||
| 444 | * status</i> of the current thread is cleared when | ||
| 445 | * this exception is thrown. | ||
| 446 | */ | ||
| 447 | public final void wait(long timeout, int nanos) throws InterruptedException { | ||
| 448 | if (timeout < 0) { | ||
| 449 | throw new IllegalArgumentException("timeout value is negative"); | ||
| 450 | } | ||
| 451 | |||
| 452 | if (nanos < 0 || nanos > 999999) { | ||
| 453 | throw new IllegalArgumentException( | ||
| 454 | "nanosecond timeout value out of range"); | ||
| 455 | } | ||
| 456 | |||
| 457 | if (nanos >= 500000 || (nanos != 0 && timeout == 0)) { | ||
| 458 | timeout++; | ||
| 459 | } | ||
| 460 | |||
| 461 | wait(timeout); | ||
| 462 | } | ||
| 463 | |||
| 464 | /** | ||
| 465 | * Causes the current thread to wait until another thread invokes the | ||
| 466 | * {@link java.lang.Object#notify()} method or the | ||
| 467 | * {@link java.lang.Object#notifyAll()} method for this object. | ||
| 468 | * In other words, this method behaves exactly as if it simply | ||
| 469 | * performs the call {@code wait(0)}. | ||
| 470 | * <p> | ||
| 471 | * The current thread must own this object's monitor. The thread | ||
| 472 | * releases ownership of this monitor and waits until another thread | ||
| 473 | * notifies threads waiting on this object's monitor to wake up | ||
| 474 | * either through a call to the {@code notify} method or the | ||
| 475 | * {@code notifyAll} method. The thread then waits until it can | ||
| 476 | * re-obtain ownership of the monitor and resumes execution. | ||
| 477 | * <p> | ||
| 478 | * As in the one argument version, interrupts and spurious wakeups are | ||
| 479 | * possible, and this method should always be used in a loop: | ||
| 480 | * <pre> | ||
| 481 | * synchronized (obj) { | ||
| 482 | * while (<condition does not hold>) | ||
| 483 | * obj.wait(); | ||
| 484 | * ... // Perform action appropriate to condition | ||
| 485 | * } | ||
| 486 | * </pre> | ||
| 487 | * This method should only be called by a thread that is the owner | ||
| 488 | * of this object's monitor. See the {@code notify} method for a | ||
| 489 | * description of the ways in which a thread can become the owner of | ||
| 490 | * a monitor. | ||
| 491 | * | ||
| 492 | * @exception IllegalMonitorStateException if the current thread is not | ||
| 493 | * the owner of the object's monitor. | ||
| 494 | * @exception InterruptedException if any thread interrupted the | ||
| 495 | * current thread before or while the current thread | ||
| 496 | * was waiting for a notification. The <i>interrupted | ||
| 497 | * status</i> of the current thread is cleared when | ||
| 498 | * this exception is thrown. | ||
| 499 | * @see java.lang.Object#notify() | ||
| 500 | * @see java.lang.Object#notifyAll() | ||
| 501 | */ | ||
| 502 | public final void wait() throws InterruptedException { | ||
| 503 | wait(0); | ||
| 504 | } | ||
| 505 | |||
| 506 | /** | ||
| 507 | * Called by the garbage collector on an object when garbage collection | ||
| 508 | * determines that there are no more references to the object. | ||
| 509 | * A subclass overrides the {@code finalize} method to dispose of | ||
| 510 | * system resources or to perform other cleanup. | ||
| 511 | * <p> | ||
| 512 | * The general contract of {@code finalize} is that it is invoked | ||
| 513 | * if and when the Java<font size="-2"><sup>TM</sup></font> virtual | ||
| 514 | * machine has determined that there is no longer any | ||
| 515 | * means by which this object can be accessed by any thread that has | ||
| 516 | * not yet died, except as a result of an action taken by the | ||
| 517 | * finalization of some other object or class which is ready to be | ||
| 518 | * finalized. The {@code finalize} method may take any action, including | ||
| 519 | * making this object available again to other threads; the usual purpose | ||
| 520 | * of {@code finalize}, however, is to perform cleanup actions before | ||
| 521 | * the object is irrevocably discarded. For example, the finalize method | ||
| 522 | * for an object that represents an input/output connection might perform | ||
| 523 | * explicit I/O transactions to break the connection before the object is | ||
| 524 | * permanently discarded. | ||
| 525 | * <p> | ||
| 526 | * The {@code finalize} method of class {@code Object} performs no | ||
| 527 | * special action; it simply returns normally. Subclasses of | ||
| 528 | * {@code Object} may override this definition. | ||
| 529 | * <p> | ||
| 530 | * The Java programming language does not guarantee which thread will | ||
| 531 | * invoke the {@code finalize} method for any given object. It is | ||
| 532 | * guaranteed, however, that the thread that invokes finalize will not | ||
| 533 | * be holding any user-visible synchronization locks when finalize is | ||
| 534 | * invoked. If an uncaught exception is thrown by the finalize method, | ||
| 535 | * the exception is ignored and finalization of that object terminates. | ||
| 536 | * <p> | ||
| 537 | * After the {@code finalize} method has been invoked for an object, no | ||
| 538 | * further action is taken until the Java virtual machine has again | ||
| 539 | * determined that there is no longer any means by which this object can | ||
| 540 | * be accessed by any thread that has not yet died, including possible | ||
| 541 | * actions by other objects or classes which are ready to be finalized, | ||
| 542 | * at which point the object may be discarded. | ||
| 543 | * <p> | ||
| 544 | * The {@code finalize} method is never invoked more than once by a Java | ||
| 545 | * virtual machine for any given object. | ||
| 546 | * <p> | ||
| 547 | * Any exception thrown by the {@code finalize} method causes | ||
| 548 | * the finalization of this object to be halted, but is otherwise | ||
| 549 | * ignored. | ||
| 550 | * | ||
| 551 | * @throws Throwable the {@code Exception} raised by this method | ||
| 552 | */ | ||
| 553 | protected void finalize() throws Throwable { } | ||
| 554 | } | ||