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.
5 * This code is free software; you can redistribute it and/or modify it
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8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
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).
17 * You should have received a copy of the GNU General Public License version
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28 import org.apidesign.bck2brwsr.core.JavaScriptBody;
31 * Class {@code Object} is the root of the class hierarchy.
32 * Every class has {@code Object} as a superclass. All objects,
33 * including arrays, implement the methods of this class.
36 * @see java.lang.Class
41 private static native void registerNatives();
47 * Returns the runtime class of this {@code Object}. The returned
48 * {@code Class} object is the object that is locked by {@code
49 * static synchronized} methods of the represented class.
51 * <p><b>The actual result type is {@code Class<? extends |X|>}
52 * where {@code |X|} is the erasure of the static type of the
53 * expression on which {@code getClass} is called.</b> For
54 * example, no cast is required in this code fragment:</p>
57 * {@code Number n = 0; }<br>
58 * {@code Class<? extends Number> c = n.getClass(); }
61 * @return The {@code Class} object that represents the runtime
62 * class of this object.
63 * @see Class Literals, section 15.8.2 of
64 * <cite>The Java™ Language Specification</cite>.
66 @JavaScriptBody(args="self", body="return self.constructor.$class;")
67 public final native Class<?> getClass();
70 * Returns a hash code value for the object. This method is
71 * supported for the benefit of hash tables such as those provided by
72 * {@link java.util.HashMap}.
74 * The general contract of {@code hashCode} is:
76 * <li>Whenever it is invoked on the same object more than once during
77 * an execution of a Java application, the {@code hashCode} method
78 * must consistently return the same integer, provided no information
79 * used in {@code equals} comparisons on the object is modified.
80 * This integer need not remain consistent from one execution of an
81 * application to another execution of the same application.
82 * <li>If two objects are equal according to the {@code equals(Object)}
83 * method, then calling the {@code hashCode} method on each of
84 * the two objects must produce the same integer result.
85 * <li>It is <em>not</em> required that if two objects are unequal
86 * according to the {@link java.lang.Object#equals(java.lang.Object)}
87 * method, then calling the {@code hashCode} method on each of the
88 * two objects must produce distinct integer results. However, the
89 * programmer should be aware that producing distinct integer results
90 * for unequal objects may improve the performance of hash tables.
93 * As much as is reasonably practical, the hashCode method defined by
94 * class {@code Object} does return distinct integers for distinct
95 * objects. (This is typically implemented by converting the internal
96 * address of the object into an integer, but this implementation
97 * technique is not required by the
98 * Java<font size="-2"><sup>TM</sup></font> programming language.)
100 * @return a hash code value for this object.
101 * @see java.lang.Object#equals(java.lang.Object)
102 * @see java.lang.System#identityHashCode
104 public native int hashCode();
107 * Indicates whether some other object is "equal to" this one.
109 * The {@code equals} method implements an equivalence relation
110 * on non-null object references:
112 * <li>It is <i>reflexive</i>: for any non-null reference value
113 * {@code x}, {@code x.equals(x)} should return
115 * <li>It is <i>symmetric</i>: for any non-null reference values
116 * {@code x} and {@code y}, {@code x.equals(y)}
117 * should return {@code true} if and only if
118 * {@code y.equals(x)} returns {@code true}.
119 * <li>It is <i>transitive</i>: for any non-null reference values
120 * {@code x}, {@code y}, and {@code z}, if
121 * {@code x.equals(y)} returns {@code true} and
122 * {@code y.equals(z)} returns {@code true}, then
123 * {@code x.equals(z)} should return {@code true}.
124 * <li>It is <i>consistent</i>: for any non-null reference values
125 * {@code x} and {@code y}, multiple invocations of
126 * {@code x.equals(y)} consistently return {@code true}
127 * or consistently return {@code false}, provided no
128 * information used in {@code equals} comparisons on the
129 * objects is modified.
130 * <li>For any non-null reference value {@code x},
131 * {@code x.equals(null)} should return {@code false}.
134 * The {@code equals} method for class {@code Object} implements
135 * the most discriminating possible equivalence relation on objects;
136 * that is, for any non-null reference values {@code x} and
137 * {@code y}, this method returns {@code true} if and only
138 * if {@code x} and {@code y} refer to the same object
139 * ({@code x == y} has the value {@code true}).
141 * Note that it is generally necessary to override the {@code hashCode}
142 * method whenever this method is overridden, so as to maintain the
143 * general contract for the {@code hashCode} method, which states
144 * that equal objects must have equal hash codes.
146 * @param obj the reference object with which to compare.
147 * @return {@code true} if this object is the same as the obj
148 * argument; {@code false} otherwise.
150 * @see java.util.HashMap
152 public boolean equals(Object obj) {
153 return (this == obj);
157 * Creates and returns a copy of this object. The precise meaning
158 * of "copy" may depend on the class of the object. The general
159 * intent is that, for any object {@code x}, the expression:
162 * x.clone() != x</pre></blockquote>
163 * will be true, and that the expression:
166 * x.clone().getClass() == x.getClass()</pre></blockquote>
167 * will be {@code true}, but these are not absolute requirements.
168 * While it is typically the case that:
171 * x.clone().equals(x)</pre></blockquote>
172 * will be {@code true}, this is not an absolute requirement.
174 * By convention, the returned object should be obtained by calling
175 * {@code super.clone}. If a class and all of its superclasses (except
176 * {@code Object}) obey this convention, it will be the case that
177 * {@code x.clone().getClass() == x.getClass()}.
179 * By convention, the object returned by this method should be independent
180 * of this object (which is being cloned). To achieve this independence,
181 * it may be necessary to modify one or more fields of the object returned
182 * by {@code super.clone} before returning it. Typically, this means
183 * copying any mutable objects that comprise the internal "deep structure"
184 * of the object being cloned and replacing the references to these
185 * objects with references to the copies. If a class contains only
186 * primitive fields or references to immutable objects, then it is usually
187 * the case that no fields in the object returned by {@code super.clone}
188 * need to be modified.
190 * The method {@code clone} for class {@code Object} performs a
191 * specific cloning operation. First, if the class of this object does
192 * not implement the interface {@code Cloneable}, then a
193 * {@code CloneNotSupportedException} is thrown. Note that all arrays
194 * are considered to implement the interface {@code Cloneable} and that
195 * the return type of the {@code clone} method of an array type {@code T[]}
196 * is {@code T[]} where T is any reference or primitive type.
197 * Otherwise, this method creates a new instance of the class of this
198 * object and initializes all its fields with exactly the contents of
199 * the corresponding fields of this object, as if by assignment; the
200 * contents of the fields are not themselves cloned. Thus, this method
201 * performs a "shallow copy" of this object, not a "deep copy" operation.
203 * The class {@code Object} does not itself implement the interface
204 * {@code Cloneable}, so calling the {@code clone} method on an object
205 * whose class is {@code Object} will result in throwing an
206 * exception at run time.
208 * @return a clone of this instance.
209 * @exception CloneNotSupportedException if the object's class does not
210 * support the {@code Cloneable} interface. Subclasses
211 * that override the {@code clone} method can also
212 * throw this exception to indicate that an instance cannot
214 * @see java.lang.Cloneable
216 protected native Object clone() throws CloneNotSupportedException;
219 * Returns a string representation of the object. In general, the
220 * {@code toString} method returns a string that
221 * "textually represents" this object. The result should
222 * be a concise but informative representation that is easy for a
224 * It is recommended that all subclasses override this method.
226 * The {@code toString} method for class {@code Object}
227 * returns a string consisting of the name of the class of which the
228 * object is an instance, the at-sign character `{@code @}', and
229 * the unsigned hexadecimal representation of the hash code of the
230 * object. In other words, this method returns a string equal to the
234 * getClass().getName() + '@' + Integer.toHexString(hashCode())
235 * </pre></blockquote>
237 * @return a string representation of the object.
239 public String toString() {
240 return getClass().getName() + "@" + Integer.toHexString(hashCode());
244 * Wakes up a single thread that is waiting on this object's
245 * monitor. If any threads are waiting on this object, one of them
246 * is chosen to be awakened. The choice is arbitrary and occurs at
247 * the discretion of the implementation. A thread waits on an object's
248 * monitor by calling one of the {@code wait} methods.
250 * The awakened thread will not be able to proceed until the current
251 * thread relinquishes the lock on this object. The awakened thread will
252 * compete in the usual manner with any other threads that might be
253 * actively competing to synchronize on this object; for example, the
254 * awakened thread enjoys no reliable privilege or disadvantage in being
255 * the next thread to lock this object.
257 * This method should only be called by a thread that is the owner
258 * of this object's monitor. A thread becomes the owner of the
259 * object's monitor in one of three ways:
261 * <li>By executing a synchronized instance method of that object.
262 * <li>By executing the body of a {@code synchronized} statement
263 * that synchronizes on the object.
264 * <li>For objects of type {@code Class,} by executing a
265 * synchronized static method of that class.
268 * Only one thread at a time can own an object's monitor.
270 * @exception IllegalMonitorStateException if the current thread is not
271 * the owner of this object's monitor.
272 * @see java.lang.Object#notifyAll()
273 * @see java.lang.Object#wait()
275 public final native void notify();
278 * Wakes up all threads that are waiting on this object's monitor. A
279 * thread waits on an object's monitor by calling one of the
280 * {@code wait} methods.
282 * The awakened threads will not be able to proceed until the current
283 * thread relinquishes the lock on this object. The awakened threads
284 * will compete in the usual manner with any other threads that might
285 * be actively competing to synchronize on this object; for example,
286 * the awakened threads enjoy no reliable privilege or disadvantage in
287 * being the next thread to lock this object.
289 * This method should only be called by a thread that is the owner
290 * of this object's monitor. See the {@code notify} method for a
291 * description of the ways in which a thread can become the owner of
294 * @exception IllegalMonitorStateException if the current thread is not
295 * the owner of this object's monitor.
296 * @see java.lang.Object#notify()
297 * @see java.lang.Object#wait()
299 public final native void notifyAll();
302 * Causes the current thread to wait until either another thread invokes the
303 * {@link java.lang.Object#notify()} method or the
304 * {@link java.lang.Object#notifyAll()} method for this object, or a
305 * specified amount of time has elapsed.
307 * The current thread must own this object's monitor.
309 * This method causes the current thread (call it <var>T</var>) to
310 * place itself in the wait set for this object and then to relinquish
311 * any and all synchronization claims on this object. Thread <var>T</var>
312 * becomes disabled for thread scheduling purposes and lies dormant
313 * until one of four things happens:
315 * <li>Some other thread invokes the {@code notify} method for this
316 * object and thread <var>T</var> happens to be arbitrarily chosen as
317 * the thread to be awakened.
318 * <li>Some other thread invokes the {@code notifyAll} method for this
320 * <li>Some other thread {@linkplain Thread#interrupt() interrupts}
321 * thread <var>T</var>.
322 * <li>The specified amount of real time has elapsed, more or less. If
323 * {@code timeout} is zero, however, then real time is not taken into
324 * consideration and the thread simply waits until notified.
326 * The thread <var>T</var> is then removed from the wait set for this
327 * object and re-enabled for thread scheduling. It then competes in the
328 * usual manner with other threads for the right to synchronize on the
329 * object; once it has gained control of the object, all its
330 * synchronization claims on the object are restored to the status quo
331 * ante - that is, to the situation as of the time that the {@code wait}
332 * method was invoked. Thread <var>T</var> then returns from the
333 * invocation of the {@code wait} method. Thus, on return from the
334 * {@code wait} method, the synchronization state of the object and of
335 * thread {@code T} is exactly as it was when the {@code wait} method
338 * A thread can also wake up without being notified, interrupted, or
339 * timing out, a so-called <i>spurious wakeup</i>. While this will rarely
340 * occur in practice, applications must guard against it by testing for
341 * the condition that should have caused the thread to be awakened, and
342 * continuing to wait if the condition is not satisfied. In other words,
343 * waits should always occur in loops, like this one:
345 * synchronized (obj) {
346 * while (<condition does not hold>)
348 * ... // Perform action appropriate to condition
351 * (For more information on this topic, see Section 3.2.3 in Doug Lea's
352 * "Concurrent Programming in Java (Second Edition)" (Addison-Wesley,
353 * 2000), or Item 50 in Joshua Bloch's "Effective Java Programming
354 * Language Guide" (Addison-Wesley, 2001).
356 * <p>If the current thread is {@linkplain java.lang.Thread#interrupt()
357 * interrupted} by any thread before or while it is waiting, then an
358 * {@code InterruptedException} is thrown. This exception is not
359 * thrown until the lock status of this object has been restored as
363 * Note that the {@code wait} method, as it places the current thread
364 * into the wait set for this object, unlocks only this object; any
365 * other objects on which the current thread may be synchronized remain
366 * locked while the thread waits.
368 * This method should only be called by a thread that is the owner
369 * of this object's monitor. See the {@code notify} method for a
370 * description of the ways in which a thread can become the owner of
373 * @param timeout the maximum time to wait in milliseconds.
374 * @exception IllegalArgumentException if the value of timeout is
376 * @exception IllegalMonitorStateException if the current thread is not
377 * the owner of the object's monitor.
378 * @exception InterruptedException if any thread interrupted the
379 * current thread before or while the current thread
380 * was waiting for a notification. The <i>interrupted
381 * status</i> of the current thread is cleared when
382 * this exception is thrown.
383 * @see java.lang.Object#notify()
384 * @see java.lang.Object#notifyAll()
386 public final native void wait(long timeout) throws InterruptedException;
389 * Causes the current thread to wait until another thread invokes the
390 * {@link java.lang.Object#notify()} method or the
391 * {@link java.lang.Object#notifyAll()} method for this object, or
392 * some other thread interrupts the current thread, or a certain
393 * amount of real time has elapsed.
395 * This method is similar to the {@code wait} method of one
396 * argument, but it allows finer control over the amount of time to
397 * wait for a notification before giving up. The amount of real time,
398 * measured in nanoseconds, is given by:
401 * 1000000*timeout+nanos</pre></blockquote>
403 * In all other respects, this method does the same thing as the
404 * method {@link #wait(long)} of one argument. In particular,
405 * {@code wait(0, 0)} means the same thing as {@code wait(0)}.
407 * The current thread must own this object's monitor. The thread
408 * releases ownership of this monitor and waits until either of the
409 * following two conditions has occurred:
411 * <li>Another thread notifies threads waiting on this object's monitor
412 * to wake up either through a call to the {@code notify} method
413 * or the {@code notifyAll} method.
414 * <li>The timeout period, specified by {@code timeout}
415 * milliseconds plus {@code nanos} nanoseconds arguments, has
419 * The thread then waits until it can re-obtain ownership of the
420 * monitor and resumes execution.
422 * As in the one argument version, interrupts and spurious wakeups are
423 * possible, and this method should always be used in a loop:
425 * synchronized (obj) {
426 * while (<condition does not hold>)
427 * obj.wait(timeout, nanos);
428 * ... // Perform action appropriate to condition
431 * This method should only be called by a thread that is the owner
432 * of this object's monitor. See the {@code notify} method for a
433 * description of the ways in which a thread can become the owner of
436 * @param timeout the maximum time to wait in milliseconds.
437 * @param nanos additional time, in nanoseconds range
439 * @exception IllegalArgumentException if the value of timeout is
440 * negative or the value of nanos is
441 * not in the range 0-999999.
442 * @exception IllegalMonitorStateException if the current thread is not
443 * the owner of this object's monitor.
444 * @exception InterruptedException if any thread interrupted the
445 * current thread before or while the current thread
446 * was waiting for a notification. The <i>interrupted
447 * status</i> of the current thread is cleared when
448 * this exception is thrown.
450 public final void wait(long timeout, int nanos) throws InterruptedException {
452 throw new IllegalArgumentException("timeout value is negative");
455 if (nanos < 0 || nanos > 999999) {
456 throw new IllegalArgumentException(
457 "nanosecond timeout value out of range");
460 if (nanos >= 500000 || (nanos != 0 && timeout == 0)) {
468 * Causes the current thread to wait until another thread invokes the
469 * {@link java.lang.Object#notify()} method or the
470 * {@link java.lang.Object#notifyAll()} method for this object.
471 * In other words, this method behaves exactly as if it simply
472 * performs the call {@code wait(0)}.
474 * The current thread must own this object's monitor. The thread
475 * releases ownership of this monitor and waits until another thread
476 * notifies threads waiting on this object's monitor to wake up
477 * either through a call to the {@code notify} method or the
478 * {@code notifyAll} method. The thread then waits until it can
479 * re-obtain ownership of the monitor and resumes execution.
481 * As in the one argument version, interrupts and spurious wakeups are
482 * possible, and this method should always be used in a loop:
484 * synchronized (obj) {
485 * while (<condition does not hold>)
487 * ... // Perform action appropriate to condition
490 * This method should only be called by a thread that is the owner
491 * of this object's monitor. See the {@code notify} method for a
492 * description of the ways in which a thread can become the owner of
495 * @exception IllegalMonitorStateException if the current thread is not
496 * the owner of the object's monitor.
497 * @exception InterruptedException if any thread interrupted the
498 * current thread before or while the current thread
499 * was waiting for a notification. The <i>interrupted
500 * status</i> of the current thread is cleared when
501 * this exception is thrown.
502 * @see java.lang.Object#notify()
503 * @see java.lang.Object#notifyAll()
505 public final void wait() throws InterruptedException {
510 * Called by the garbage collector on an object when garbage collection
511 * determines that there are no more references to the object.
512 * A subclass overrides the {@code finalize} method to dispose of
513 * system resources or to perform other cleanup.
515 * The general contract of {@code finalize} is that it is invoked
516 * if and when the Java<font size="-2"><sup>TM</sup></font> virtual
517 * machine has determined that there is no longer any
518 * means by which this object can be accessed by any thread that has
519 * not yet died, except as a result of an action taken by the
520 * finalization of some other object or class which is ready to be
521 * finalized. The {@code finalize} method may take any action, including
522 * making this object available again to other threads; the usual purpose
523 * of {@code finalize}, however, is to perform cleanup actions before
524 * the object is irrevocably discarded. For example, the finalize method
525 * for an object that represents an input/output connection might perform
526 * explicit I/O transactions to break the connection before the object is
527 * permanently discarded.
529 * The {@code finalize} method of class {@code Object} performs no
530 * special action; it simply returns normally. Subclasses of
531 * {@code Object} may override this definition.
533 * The Java programming language does not guarantee which thread will
534 * invoke the {@code finalize} method for any given object. It is
535 * guaranteed, however, that the thread that invokes finalize will not
536 * be holding any user-visible synchronization locks when finalize is
537 * invoked. If an uncaught exception is thrown by the finalize method,
538 * the exception is ignored and finalization of that object terminates.
540 * After the {@code finalize} method has been invoked for an object, no
541 * further action is taken until the Java virtual machine has again
542 * determined that there is no longer any means by which this object can
543 * be accessed by any thread that has not yet died, including possible
544 * actions by other objects or classes which are ready to be finalized,
545 * at which point the object may be discarded.
547 * The {@code finalize} method is never invoked more than once by a Java
548 * virtual machine for any given object.
550 * Any exception thrown by the {@code finalize} method causes
551 * the finalization of this object to be halted, but is otherwise
554 * @throws Throwable the {@code Exception} raised by this method
556 protected void finalize() throws Throwable { }