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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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).
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28 import org.apidesign.bck2brwsr.core.JavaScriptBody;
29 import org.apidesign.bck2brwsr.core.JavaScriptPrototype;
32 * Class {@code Object} is the root of the class hierarchy.
33 * Every class has {@code Object} as a superclass. All objects,
34 * including arrays, implement the methods of this class.
37 * @see java.lang.Class
40 @JavaScriptPrototype(container = "Object.prototype", prototype = "new Object")
43 @JavaScriptBody(args = {}, body = "")
44 private static native void registerNatives();
50 * Returns the runtime class of this {@code Object}. The returned
51 * {@code Class} object is the object that is locked by {@code
52 * static synchronized} methods of the represented class.
54 * <p><b>The actual result type is {@code Class<? extends |X|>}
55 * where {@code |X|} is the erasure of the static type of the
56 * expression on which {@code getClass} is called.</b> For
57 * example, no cast is required in this code fragment:</p>
60 * {@code Number n = 0; }<br>
61 * {@code Class<? extends Number> c = n.getClass(); }
64 * @return The {@code Class} object that represents the runtime
65 * class of this object.
66 * @see Class Literals, section 15.8.2 of
67 * <cite>The Java™ Language Specification</cite>.
69 @JavaScriptBody(args="self", body="return self.constructor.$class;")
70 public final native Class<?> getClass();
73 * Returns a hash code value for the object. This method is
74 * supported for the benefit of hash tables such as those provided by
75 * {@link java.util.HashMap}.
77 * The general contract of {@code hashCode} is:
79 * <li>Whenever it is invoked on the same object more than once during
80 * an execution of a Java application, the {@code hashCode} method
81 * must consistently return the same integer, provided no information
82 * used in {@code equals} comparisons on the object is modified.
83 * This integer need not remain consistent from one execution of an
84 * application to another execution of the same application.
85 * <li>If two objects are equal according to the {@code equals(Object)}
86 * method, then calling the {@code hashCode} method on each of
87 * the two objects must produce the same integer result.
88 * <li>It is <em>not</em> required that if two objects are unequal
89 * according to the {@link java.lang.Object#equals(java.lang.Object)}
90 * method, then calling the {@code hashCode} method on each of the
91 * two objects must produce distinct integer results. However, the
92 * programmer should be aware that producing distinct integer results
93 * for unequal objects may improve the performance of hash tables.
96 * As much as is reasonably practical, the hashCode method defined by
97 * class {@code Object} does return distinct integers for distinct
98 * objects. (This is typically implemented by converting the internal
99 * address of the object into an integer, but this implementation
100 * technique is not required by the
101 * Java<font size="-2"><sup>TM</sup></font> programming language.)
103 * @return a hash code value for this object.
104 * @see java.lang.Object#equals(java.lang.Object)
105 * @see java.lang.System#identityHashCode
107 public native int hashCode();
110 * Indicates whether some other object is "equal to" this one.
112 * The {@code equals} method implements an equivalence relation
113 * on non-null object references:
115 * <li>It is <i>reflexive</i>: for any non-null reference value
116 * {@code x}, {@code x.equals(x)} should return
118 * <li>It is <i>symmetric</i>: for any non-null reference values
119 * {@code x} and {@code y}, {@code x.equals(y)}
120 * should return {@code true} if and only if
121 * {@code y.equals(x)} returns {@code true}.
122 * <li>It is <i>transitive</i>: for any non-null reference values
123 * {@code x}, {@code y}, and {@code z}, if
124 * {@code x.equals(y)} returns {@code true} and
125 * {@code y.equals(z)} returns {@code true}, then
126 * {@code x.equals(z)} should return {@code true}.
127 * <li>It is <i>consistent</i>: for any non-null reference values
128 * {@code x} and {@code y}, multiple invocations of
129 * {@code x.equals(y)} consistently return {@code true}
130 * or consistently return {@code false}, provided no
131 * information used in {@code equals} comparisons on the
132 * objects is modified.
133 * <li>For any non-null reference value {@code x},
134 * {@code x.equals(null)} should return {@code false}.
137 * The {@code equals} method for class {@code Object} implements
138 * the most discriminating possible equivalence relation on objects;
139 * that is, for any non-null reference values {@code x} and
140 * {@code y}, this method returns {@code true} if and only
141 * if {@code x} and {@code y} refer to the same object
142 * ({@code x == y} has the value {@code true}).
144 * Note that it is generally necessary to override the {@code hashCode}
145 * method whenever this method is overridden, so as to maintain the
146 * general contract for the {@code hashCode} method, which states
147 * that equal objects must have equal hash codes.
149 * @param obj the reference object with which to compare.
150 * @return {@code true} if this object is the same as the obj
151 * argument; {@code false} otherwise.
153 * @see java.util.HashMap
155 public boolean equals(Object obj) {
156 return (this == obj);
160 * Creates and returns a copy of this object. The precise meaning
161 * of "copy" may depend on the class of the object. The general
162 * intent is that, for any object {@code x}, the expression:
165 * x.clone() != x</pre></blockquote>
166 * will be true, and that the expression:
169 * x.clone().getClass() == x.getClass()</pre></blockquote>
170 * will be {@code true}, but these are not absolute requirements.
171 * While it is typically the case that:
174 * x.clone().equals(x)</pre></blockquote>
175 * will be {@code true}, this is not an absolute requirement.
177 * By convention, the returned object should be obtained by calling
178 * {@code super.clone}. If a class and all of its superclasses (except
179 * {@code Object}) obey this convention, it will be the case that
180 * {@code x.clone().getClass() == x.getClass()}.
182 * By convention, the object returned by this method should be independent
183 * of this object (which is being cloned). To achieve this independence,
184 * it may be necessary to modify one or more fields of the object returned
185 * by {@code super.clone} before returning it. Typically, this means
186 * copying any mutable objects that comprise the internal "deep structure"
187 * of the object being cloned and replacing the references to these
188 * objects with references to the copies. If a class contains only
189 * primitive fields or references to immutable objects, then it is usually
190 * the case that no fields in the object returned by {@code super.clone}
191 * need to be modified.
193 * The method {@code clone} for class {@code Object} performs a
194 * specific cloning operation. First, if the class of this object does
195 * not implement the interface {@code Cloneable}, then a
196 * {@code CloneNotSupportedException} is thrown. Note that all arrays
197 * are considered to implement the interface {@code Cloneable} and that
198 * the return type of the {@code clone} method of an array type {@code T[]}
199 * is {@code T[]} where T is any reference or primitive type.
200 * Otherwise, this method creates a new instance of the class of this
201 * object and initializes all its fields with exactly the contents of
202 * the corresponding fields of this object, as if by assignment; the
203 * contents of the fields are not themselves cloned. Thus, this method
204 * performs a "shallow copy" of this object, not a "deep copy" operation.
206 * The class {@code Object} does not itself implement the interface
207 * {@code Cloneable}, so calling the {@code clone} method on an object
208 * whose class is {@code Object} will result in throwing an
209 * exception at run time.
211 * @return a clone of this instance.
212 * @exception CloneNotSupportedException if the object's class does not
213 * support the {@code Cloneable} interface. Subclasses
214 * that override the {@code clone} method can also
215 * throw this exception to indicate that an instance cannot
217 * @see java.lang.Cloneable
219 protected native Object clone() throws CloneNotSupportedException;
222 * Returns a string representation of the object. In general, the
223 * {@code toString} method returns a string that
224 * "textually represents" this object. The result should
225 * be a concise but informative representation that is easy for a
227 * It is recommended that all subclasses override this method.
229 * The {@code toString} method for class {@code Object}
230 * returns a string consisting of the name of the class of which the
231 * object is an instance, the at-sign character `{@code @}', and
232 * the unsigned hexadecimal representation of the hash code of the
233 * object. In other words, this method returns a string equal to the
237 * getClass().getName() + '@' + Integer.toHexString(hashCode())
238 * </pre></blockquote>
240 * @return a string representation of the object.
242 public String toString() {
243 return getClass().getName() + "@" + Integer.toHexString(hashCode());
247 * Wakes up a single thread that is waiting on this object's
248 * monitor. If any threads are waiting on this object, one of them
249 * is chosen to be awakened. The choice is arbitrary and occurs at
250 * the discretion of the implementation. A thread waits on an object's
251 * monitor by calling one of the {@code wait} methods.
253 * The awakened thread will not be able to proceed until the current
254 * thread relinquishes the lock on this object. The awakened thread will
255 * compete in the usual manner with any other threads that might be
256 * actively competing to synchronize on this object; for example, the
257 * awakened thread enjoys no reliable privilege or disadvantage in being
258 * the next thread to lock this object.
260 * This method should only be called by a thread that is the owner
261 * of this object's monitor. A thread becomes the owner of the
262 * object's monitor in one of three ways:
264 * <li>By executing a synchronized instance method of that object.
265 * <li>By executing the body of a {@code synchronized} statement
266 * that synchronizes on the object.
267 * <li>For objects of type {@code Class,} by executing a
268 * synchronized static method of that class.
271 * Only one thread at a time can own an object's monitor.
273 * @exception IllegalMonitorStateException if the current thread is not
274 * the owner of this object's monitor.
275 * @see java.lang.Object#notifyAll()
276 * @see java.lang.Object#wait()
278 public final native void notify();
281 * Wakes up all threads that are waiting on this object's monitor. A
282 * thread waits on an object's monitor by calling one of the
283 * {@code wait} methods.
285 * The awakened threads will not be able to proceed until the current
286 * thread relinquishes the lock on this object. The awakened threads
287 * will compete in the usual manner with any other threads that might
288 * be actively competing to synchronize on this object; for example,
289 * the awakened threads enjoy no reliable privilege or disadvantage in
290 * being the next thread to lock this object.
292 * This method should only be called by a thread that is the owner
293 * of this object's monitor. See the {@code notify} method for a
294 * description of the ways in which a thread can become the owner of
297 * @exception IllegalMonitorStateException if the current thread is not
298 * the owner of this object's monitor.
299 * @see java.lang.Object#notify()
300 * @see java.lang.Object#wait()
302 public final native void notifyAll();
305 * Causes the current thread to wait until either another thread invokes the
306 * {@link java.lang.Object#notify()} method or the
307 * {@link java.lang.Object#notifyAll()} method for this object, or a
308 * specified amount of time has elapsed.
310 * The current thread must own this object's monitor.
312 * This method causes the current thread (call it <var>T</var>) to
313 * place itself in the wait set for this object and then to relinquish
314 * any and all synchronization claims on this object. Thread <var>T</var>
315 * becomes disabled for thread scheduling purposes and lies dormant
316 * until one of four things happens:
318 * <li>Some other thread invokes the {@code notify} method for this
319 * object and thread <var>T</var> happens to be arbitrarily chosen as
320 * the thread to be awakened.
321 * <li>Some other thread invokes the {@code notifyAll} method for this
323 * <li>Some other thread {@linkplain Thread#interrupt() interrupts}
324 * thread <var>T</var>.
325 * <li>The specified amount of real time has elapsed, more or less. If
326 * {@code timeout} is zero, however, then real time is not taken into
327 * consideration and the thread simply waits until notified.
329 * The thread <var>T</var> is then removed from the wait set for this
330 * object and re-enabled for thread scheduling. It then competes in the
331 * usual manner with other threads for the right to synchronize on the
332 * object; once it has gained control of the object, all its
333 * synchronization claims on the object are restored to the status quo
334 * ante - that is, to the situation as of the time that the {@code wait}
335 * method was invoked. Thread <var>T</var> then returns from the
336 * invocation of the {@code wait} method. Thus, on return from the
337 * {@code wait} method, the synchronization state of the object and of
338 * thread {@code T} is exactly as it was when the {@code wait} method
341 * A thread can also wake up without being notified, interrupted, or
342 * timing out, a so-called <i>spurious wakeup</i>. While this will rarely
343 * occur in practice, applications must guard against it by testing for
344 * the condition that should have caused the thread to be awakened, and
345 * continuing to wait if the condition is not satisfied. In other words,
346 * waits should always occur in loops, like this one:
348 * synchronized (obj) {
349 * while (<condition does not hold>)
351 * ... // Perform action appropriate to condition
354 * (For more information on this topic, see Section 3.2.3 in Doug Lea's
355 * "Concurrent Programming in Java (Second Edition)" (Addison-Wesley,
356 * 2000), or Item 50 in Joshua Bloch's "Effective Java Programming
357 * Language Guide" (Addison-Wesley, 2001).
359 * <p>If the current thread is {@linkplain java.lang.Thread#interrupt()
360 * interrupted} by any thread before or while it is waiting, then an
361 * {@code InterruptedException} is thrown. This exception is not
362 * thrown until the lock status of this object has been restored as
366 * Note that the {@code wait} method, as it places the current thread
367 * into the wait set for this object, unlocks only this object; any
368 * other objects on which the current thread may be synchronized remain
369 * locked while the thread waits.
371 * This method should only be called by a thread that is the owner
372 * of this object's monitor. See the {@code notify} method for a
373 * description of the ways in which a thread can become the owner of
376 * @param timeout the maximum time to wait in milliseconds.
377 * @exception IllegalArgumentException if the value of timeout is
379 * @exception IllegalMonitorStateException if the current thread is not
380 * the owner of the object's monitor.
381 * @exception InterruptedException if any thread interrupted the
382 * current thread before or while the current thread
383 * was waiting for a notification. The <i>interrupted
384 * status</i> of the current thread is cleared when
385 * this exception is thrown.
386 * @see java.lang.Object#notify()
387 * @see java.lang.Object#notifyAll()
389 public final native void wait(long timeout) throws InterruptedException;
392 * Causes the current thread to wait until another thread invokes the
393 * {@link java.lang.Object#notify()} method or the
394 * {@link java.lang.Object#notifyAll()} method for this object, or
395 * some other thread interrupts the current thread, or a certain
396 * amount of real time has elapsed.
398 * This method is similar to the {@code wait} method of one
399 * argument, but it allows finer control over the amount of time to
400 * wait for a notification before giving up. The amount of real time,
401 * measured in nanoseconds, is given by:
404 * 1000000*timeout+nanos</pre></blockquote>
406 * In all other respects, this method does the same thing as the
407 * method {@link #wait(long)} of one argument. In particular,
408 * {@code wait(0, 0)} means the same thing as {@code wait(0)}.
410 * The current thread must own this object's monitor. The thread
411 * releases ownership of this monitor and waits until either of the
412 * following two conditions has occurred:
414 * <li>Another thread notifies threads waiting on this object's monitor
415 * to wake up either through a call to the {@code notify} method
416 * or the {@code notifyAll} method.
417 * <li>The timeout period, specified by {@code timeout}
418 * milliseconds plus {@code nanos} nanoseconds arguments, has
422 * The thread then waits until it can re-obtain ownership of the
423 * monitor and resumes execution.
425 * As in the one argument version, interrupts and spurious wakeups are
426 * possible, and this method should always be used in a loop:
428 * synchronized (obj) {
429 * while (<condition does not hold>)
430 * obj.wait(timeout, nanos);
431 * ... // Perform action appropriate to condition
434 * This method should only be called by a thread that is the owner
435 * of this object's monitor. See the {@code notify} method for a
436 * description of the ways in which a thread can become the owner of
439 * @param timeout the maximum time to wait in milliseconds.
440 * @param nanos additional time, in nanoseconds range
442 * @exception IllegalArgumentException if the value of timeout is
443 * negative or the value of nanos is
444 * not in the range 0-999999.
445 * @exception IllegalMonitorStateException if the current thread is not
446 * the owner of this object's monitor.
447 * @exception InterruptedException if any thread interrupted the
448 * current thread before or while the current thread
449 * was waiting for a notification. The <i>interrupted
450 * status</i> of the current thread is cleared when
451 * this exception is thrown.
453 public final void wait(long timeout, int nanos) throws InterruptedException {
455 throw new IllegalArgumentException("timeout value is negative");
458 if (nanos < 0 || nanos > 999999) {
459 throw new IllegalArgumentException(
460 "nanosecond timeout value out of range");
463 if (nanos >= 500000 || (nanos != 0 && timeout == 0)) {
471 * Causes the current thread to wait until another thread invokes the
472 * {@link java.lang.Object#notify()} method or the
473 * {@link java.lang.Object#notifyAll()} method for this object.
474 * In other words, this method behaves exactly as if it simply
475 * performs the call {@code wait(0)}.
477 * The current thread must own this object's monitor. The thread
478 * releases ownership of this monitor and waits until another thread
479 * notifies threads waiting on this object's monitor to wake up
480 * either through a call to the {@code notify} method or the
481 * {@code notifyAll} method. The thread then waits until it can
482 * re-obtain ownership of the monitor and resumes execution.
484 * As in the one argument version, interrupts and spurious wakeups are
485 * possible, and this method should always be used in a loop:
487 * synchronized (obj) {
488 * while (<condition does not hold>)
490 * ... // Perform action appropriate to condition
493 * This method should only be called by a thread that is the owner
494 * of this object's monitor. See the {@code notify} method for a
495 * description of the ways in which a thread can become the owner of
498 * @exception IllegalMonitorStateException if the current thread is not
499 * the owner of the object's monitor.
500 * @exception InterruptedException if any thread interrupted the
501 * current thread before or while the current thread
502 * was waiting for a notification. The <i>interrupted
503 * status</i> of the current thread is cleared when
504 * this exception is thrown.
505 * @see java.lang.Object#notify()
506 * @see java.lang.Object#notifyAll()
508 public final void wait() throws InterruptedException {
513 * Called by the garbage collector on an object when garbage collection
514 * determines that there are no more references to the object.
515 * A subclass overrides the {@code finalize} method to dispose of
516 * system resources or to perform other cleanup.
518 * The general contract of {@code finalize} is that it is invoked
519 * if and when the Java<font size="-2"><sup>TM</sup></font> virtual
520 * machine has determined that there is no longer any
521 * means by which this object can be accessed by any thread that has
522 * not yet died, except as a result of an action taken by the
523 * finalization of some other object or class which is ready to be
524 * finalized. The {@code finalize} method may take any action, including
525 * making this object available again to other threads; the usual purpose
526 * of {@code finalize}, however, is to perform cleanup actions before
527 * the object is irrevocably discarded. For example, the finalize method
528 * for an object that represents an input/output connection might perform
529 * explicit I/O transactions to break the connection before the object is
530 * permanently discarded.
532 * The {@code finalize} method of class {@code Object} performs no
533 * special action; it simply returns normally. Subclasses of
534 * {@code Object} may override this definition.
536 * The Java programming language does not guarantee which thread will
537 * invoke the {@code finalize} method for any given object. It is
538 * guaranteed, however, that the thread that invokes finalize will not
539 * be holding any user-visible synchronization locks when finalize is
540 * invoked. If an uncaught exception is thrown by the finalize method,
541 * the exception is ignored and finalization of that object terminates.
543 * After the {@code finalize} method has been invoked for an object, no
544 * further action is taken until the Java virtual machine has again
545 * determined that there is no longer any means by which this object can
546 * be accessed by any thread that has not yet died, including possible
547 * actions by other objects or classes which are ready to be finalized,
548 * at which point the object may be discarded.
550 * The {@code finalize} method is never invoked more than once by a Java
551 * virtual machine for any given object.
553 * Any exception thrown by the {@code finalize} method causes
554 * the finalization of this object to be halted, but is otherwise
557 * @throws Throwable the {@code Exception} raised by this method
559 protected void finalize() throws Throwable { }