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
6 * under the terms of the GNU General Public License version 2 only, as
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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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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
28 import java.lang.reflect.Array;
29 import org.apidesign.bck2brwsr.core.JavaScriptBody;
30 import org.apidesign.bck2brwsr.core.JavaScriptPrototype;
33 * Class {@code Object} is the root of the class hierarchy.
34 * Every class has {@code Object} as a superclass. All objects,
35 * including arrays, implement the methods of this class.
38 * @see java.lang.Class
41 @JavaScriptPrototype(container = "Object.prototype", prototype = "new Object")
44 private static void registerNatives() {
45 boolean assertsOn = false;
46 assert assertsOn = false;
49 } catch (Throwable ex) {
53 @JavaScriptBody(args = {}, body = "var p = vm.java_lang_Object(false);" +
54 "p.toString = function() { return this.toString__Ljava_lang_String_2(); };"
56 private static native void registerToString();
63 * Returns the runtime class of this {@code Object}. The returned
64 * {@code Class} object is the object that is locked by {@code
65 * static synchronized} methods of the represented class.
67 * <p><b>The actual result type is {@code Class<? extends |X|>}
68 * where {@code |X|} is the erasure of the static type of the
69 * expression on which {@code getClass} is called.</b> For
70 * example, no cast is required in this code fragment:</p>
73 * {@code Number n = 0; }<br>
74 * {@code Class<? extends Number> c = n.getClass(); }
77 * @return The {@code Class} object that represents the runtime
78 * class of this object.
79 * @see Class Literals, section 15.8.2 of
80 * <cite>The Java™ Language Specification</cite>.
82 public final Class<?> getClass() {
83 Class<?> c = getClassImpl();
84 return c == null ? Object.class : c;
87 @JavaScriptBody(args={}, body=
88 "var c = this.constructor.$class;\n"
89 + "return c ? c : null;\n"
91 private final native Class<?> getClassImpl();
94 * Returns a hash code value for the object. This method is
95 * supported for the benefit of hash tables such as those provided by
96 * {@link java.util.HashMap}.
98 * The general contract of {@code hashCode} is:
100 * <li>Whenever it is invoked on the same object more than once during
101 * an execution of a Java application, the {@code hashCode} method
102 * must consistently return the same integer, provided no information
103 * used in {@code equals} comparisons on the object is modified.
104 * This integer need not remain consistent from one execution of an
105 * application to another execution of the same application.
106 * <li>If two objects are equal according to the {@code equals(Object)}
107 * method, then calling the {@code hashCode} method on each of
108 * the two objects must produce the same integer result.
109 * <li>It is <em>not</em> required that if two objects are unequal
110 * according to the {@link java.lang.Object#equals(java.lang.Object)}
111 * method, then calling the {@code hashCode} method on each of the
112 * two objects must produce distinct integer results. However, the
113 * programmer should be aware that producing distinct integer results
114 * for unequal objects may improve the performance of hash tables.
117 * As much as is reasonably practical, the hashCode method defined by
118 * class {@code Object} does return distinct integers for distinct
119 * objects. (This is typically implemented by converting the internal
120 * address of the object into an integer, but this implementation
121 * technique is not required by the
122 * Java<font size="-2"><sup>TM</sup></font> programming language.)
124 * @return a hash code value for this object.
125 * @see java.lang.Object#equals(java.lang.Object)
126 * @see java.lang.System#identityHashCode
128 public int hashCode() {
129 return defaultHashCode();
131 @JavaScriptBody(args = {}, body =
132 "if (this.$hashCode) return this.$hashCode;\n"
133 + "var h = this.computeHashCode__I();\n"
134 + "return this.$hashCode = h & h;"
136 final native int defaultHashCode();
138 @JavaScriptBody(args = {}, body = "return Math.random() * Math.pow(2, 32);")
139 native int computeHashCode();
142 * Indicates whether some other object is "equal to" this one.
144 * The {@code equals} method implements an equivalence relation
145 * on non-null object references:
147 * <li>It is <i>reflexive</i>: for any non-null reference value
148 * {@code x}, {@code x.equals(x)} should return
150 * <li>It is <i>symmetric</i>: for any non-null reference values
151 * {@code x} and {@code y}, {@code x.equals(y)}
152 * should return {@code true} if and only if
153 * {@code y.equals(x)} returns {@code true}.
154 * <li>It is <i>transitive</i>: for any non-null reference values
155 * {@code x}, {@code y}, and {@code z}, if
156 * {@code x.equals(y)} returns {@code true} and
157 * {@code y.equals(z)} returns {@code true}, then
158 * {@code x.equals(z)} should return {@code true}.
159 * <li>It is <i>consistent</i>: for any non-null reference values
160 * {@code x} and {@code y}, multiple invocations of
161 * {@code x.equals(y)} consistently return {@code true}
162 * or consistently return {@code false}, provided no
163 * information used in {@code equals} comparisons on the
164 * objects is modified.
165 * <li>For any non-null reference value {@code x},
166 * {@code x.equals(null)} should return {@code false}.
169 * The {@code equals} method for class {@code Object} implements
170 * the most discriminating possible equivalence relation on objects;
171 * that is, for any non-null reference values {@code x} and
172 * {@code y}, this method returns {@code true} if and only
173 * if {@code x} and {@code y} refer to the same object
174 * ({@code x == y} has the value {@code true}).
176 * Note that it is generally necessary to override the {@code hashCode}
177 * method whenever this method is overridden, so as to maintain the
178 * general contract for the {@code hashCode} method, which states
179 * that equal objects must have equal hash codes.
181 * @param obj the reference object with which to compare.
182 * @return {@code true} if this object is the same as the obj
183 * argument; {@code false} otherwise.
185 * @see java.util.HashMap
187 public boolean equals(Object obj) {
188 return (this == obj);
192 * Creates and returns a copy of this object. The precise meaning
193 * of "copy" may depend on the class of the object. The general
194 * intent is that, for any object {@code x}, the expression:
197 * x.clone() != x</pre></blockquote>
198 * will be true, and that the expression:
201 * x.clone().getClass() == x.getClass()</pre></blockquote>
202 * will be {@code true}, but these are not absolute requirements.
203 * While it is typically the case that:
206 * x.clone().equals(x)</pre></blockquote>
207 * will be {@code true}, this is not an absolute requirement.
209 * By convention, the returned object should be obtained by calling
210 * {@code super.clone}. If a class and all of its superclasses (except
211 * {@code Object}) obey this convention, it will be the case that
212 * {@code x.clone().getClass() == x.getClass()}.
214 * By convention, the object returned by this method should be independent
215 * of this object (which is being cloned). To achieve this independence,
216 * it may be necessary to modify one or more fields of the object returned
217 * by {@code super.clone} before returning it. Typically, this means
218 * copying any mutable objects that comprise the internal "deep structure"
219 * of the object being cloned and replacing the references to these
220 * objects with references to the copies. If a class contains only
221 * primitive fields or references to immutable objects, then it is usually
222 * the case that no fields in the object returned by {@code super.clone}
223 * need to be modified.
225 * The method {@code clone} for class {@code Object} performs a
226 * specific cloning operation. First, if the class of this object does
227 * not implement the interface {@code Cloneable}, then a
228 * {@code CloneNotSupportedException} is thrown. Note that all arrays
229 * are considered to implement the interface {@code Cloneable} and that
230 * the return type of the {@code clone} method of an array type {@code T[]}
231 * is {@code T[]} where T is any reference or primitive type.
232 * Otherwise, this method creates a new instance of the class of this
233 * object and initializes all its fields with exactly the contents of
234 * the corresponding fields of this object, as if by assignment; the
235 * contents of the fields are not themselves cloned. Thus, this method
236 * performs a "shallow copy" of this object, not a "deep copy" operation.
238 * The class {@code Object} does not itself implement the interface
239 * {@code Cloneable}, so calling the {@code clone} method on an object
240 * whose class is {@code Object} will result in throwing an
241 * exception at run time.
243 * @return a clone of this instance.
244 * @exception CloneNotSupportedException if the object's class does not
245 * support the {@code Cloneable} interface. Subclasses
246 * that override the {@code clone} method can also
247 * throw this exception to indicate that an instance cannot
249 * @see java.lang.Cloneable
251 protected Object clone() throws CloneNotSupportedException {
252 Object ret = clone(this);
254 throw new CloneNotSupportedException(getClass().getName());
259 @JavaScriptBody(args = "self", body =
260 "\nif (!self.$instOf_java_lang_Cloneable) {"
263 + "\n var clone = self.constructor(true);"
264 + "\n var props = Object.getOwnPropertyNames(self);"
265 + "\n for (var i = 0; i < props.length; i++) {"
266 + "\n var p = props[i];"
267 + "\n clone[p] = self[p];"
272 private static native Object clone(Object self) throws CloneNotSupportedException;
275 * Returns a string representation of the object. In general, the
276 * {@code toString} method returns a string that
277 * "textually represents" this object. The result should
278 * be a concise but informative representation that is easy for a
280 * It is recommended that all subclasses override this method.
282 * The {@code toString} method for class {@code Object}
283 * returns a string consisting of the name of the class of which the
284 * object is an instance, the at-sign character `{@code @}', and
285 * the unsigned hexadecimal representation of the hash code of the
286 * object. In other words, this method returns a string equal to the
290 * getClass().getName() + '@' + Integer.toHexString(hashCode())
291 * </pre></blockquote>
293 * @return a string representation of the object.
295 public String toString() {
296 return getClass().getName() + "@" + Integer.toHexString(hashCode());
300 * Wakes up a single thread that is waiting on this object's
301 * monitor. If any threads are waiting on this object, one of them
302 * is chosen to be awakened. The choice is arbitrary and occurs at
303 * the discretion of the implementation. A thread waits on an object's
304 * monitor by calling one of the {@code wait} methods.
306 * The awakened thread will not be able to proceed until the current
307 * thread relinquishes the lock on this object. The awakened thread will
308 * compete in the usual manner with any other threads that might be
309 * actively competing to synchronize on this object; for example, the
310 * awakened thread enjoys no reliable privilege or disadvantage in being
311 * the next thread to lock this object.
313 * This method should only be called by a thread that is the owner
314 * of this object's monitor. A thread becomes the owner of the
315 * object's monitor in one of three ways:
317 * <li>By executing a synchronized instance method of that object.
318 * <li>By executing the body of a {@code synchronized} statement
319 * that synchronizes on the object.
320 * <li>For objects of type {@code Class,} by executing a
321 * synchronized static method of that class.
324 * Only one thread at a time can own an object's monitor.
326 * @exception IllegalMonitorStateException if the current thread is not
327 * the owner of this object's monitor.
328 * @see java.lang.Object#notifyAll()
329 * @see java.lang.Object#wait()
331 public final native void notify();
334 * Wakes up all threads that are waiting on this object's monitor. A
335 * thread waits on an object's monitor by calling one of the
336 * {@code wait} methods.
338 * The awakened threads will not be able to proceed until the current
339 * thread relinquishes the lock on this object. The awakened threads
340 * will compete in the usual manner with any other threads that might
341 * be actively competing to synchronize on this object; for example,
342 * the awakened threads enjoy no reliable privilege or disadvantage in
343 * being the next thread to lock this object.
345 * This method should only be called by a thread that is the owner
346 * of this object's monitor. See the {@code notify} method for a
347 * description of the ways in which a thread can become the owner of
350 * @exception IllegalMonitorStateException if the current thread is not
351 * the owner of this object's monitor.
352 * @see java.lang.Object#notify()
353 * @see java.lang.Object#wait()
355 public final native void notifyAll();
358 * Causes the current thread to wait until either another thread invokes the
359 * {@link java.lang.Object#notify()} method or the
360 * {@link java.lang.Object#notifyAll()} method for this object, or a
361 * specified amount of time has elapsed.
363 * The current thread must own this object's monitor.
365 * This method causes the current thread (call it <var>T</var>) to
366 * place itself in the wait set for this object and then to relinquish
367 * any and all synchronization claims on this object. Thread <var>T</var>
368 * becomes disabled for thread scheduling purposes and lies dormant
369 * until one of four things happens:
371 * <li>Some other thread invokes the {@code notify} method for this
372 * object and thread <var>T</var> happens to be arbitrarily chosen as
373 * the thread to be awakened.
374 * <li>Some other thread invokes the {@code notifyAll} method for this
376 * <li>Some other thread {@linkplain Thread#interrupt() interrupts}
377 * thread <var>T</var>.
378 * <li>The specified amount of real time has elapsed, more or less. If
379 * {@code timeout} is zero, however, then real time is not taken into
380 * consideration and the thread simply waits until notified.
382 * The thread <var>T</var> is then removed from the wait set for this
383 * object and re-enabled for thread scheduling. It then competes in the
384 * usual manner with other threads for the right to synchronize on the
385 * object; once it has gained control of the object, all its
386 * synchronization claims on the object are restored to the status quo
387 * ante - that is, to the situation as of the time that the {@code wait}
388 * method was invoked. Thread <var>T</var> then returns from the
389 * invocation of the {@code wait} method. Thus, on return from the
390 * {@code wait} method, the synchronization state of the object and of
391 * thread {@code T} is exactly as it was when the {@code wait} method
394 * A thread can also wake up without being notified, interrupted, or
395 * timing out, a so-called <i>spurious wakeup</i>. While this will rarely
396 * occur in practice, applications must guard against it by testing for
397 * the condition that should have caused the thread to be awakened, and
398 * continuing to wait if the condition is not satisfied. In other words,
399 * waits should always occur in loops, like this one:
401 * synchronized (obj) {
402 * while (<condition does not hold>)
404 * ... // Perform action appropriate to condition
407 * (For more information on this topic, see Section 3.2.3 in Doug Lea's
408 * "Concurrent Programming in Java (Second Edition)" (Addison-Wesley,
409 * 2000), or Item 50 in Joshua Bloch's "Effective Java Programming
410 * Language Guide" (Addison-Wesley, 2001).
412 * <p>If the current thread is {@linkplain java.lang.Thread#interrupt()
413 * interrupted} by any thread before or while it is waiting, then an
414 * {@code InterruptedException} is thrown. This exception is not
415 * thrown until the lock status of this object has been restored as
419 * Note that the {@code wait} method, as it places the current thread
420 * into the wait set for this object, unlocks only this object; any
421 * other objects on which the current thread may be synchronized remain
422 * locked while the thread waits.
424 * This method should only be called by a thread that is the owner
425 * of this object's monitor. See the {@code notify} method for a
426 * description of the ways in which a thread can become the owner of
429 * @param timeout the maximum time to wait in milliseconds.
430 * @exception IllegalArgumentException if the value of timeout is
432 * @exception IllegalMonitorStateException if the current thread is not
433 * the owner of the object's monitor.
434 * @exception InterruptedException if any thread interrupted the
435 * current thread before or while the current thread
436 * was waiting for a notification. The <i>interrupted
437 * status</i> of the current thread is cleared when
438 * this exception is thrown.
439 * @see java.lang.Object#notify()
440 * @see java.lang.Object#notifyAll()
442 public final native void wait(long timeout) throws InterruptedException;
445 * Causes the current thread to wait until another thread invokes the
446 * {@link java.lang.Object#notify()} method or the
447 * {@link java.lang.Object#notifyAll()} method for this object, or
448 * some other thread interrupts the current thread, or a certain
449 * amount of real time has elapsed.
451 * This method is similar to the {@code wait} method of one
452 * argument, but it allows finer control over the amount of time to
453 * wait for a notification before giving up. The amount of real time,
454 * measured in nanoseconds, is given by:
457 * 1000000*timeout+nanos</pre></blockquote>
459 * In all other respects, this method does the same thing as the
460 * method {@link #wait(long)} of one argument. In particular,
461 * {@code wait(0, 0)} means the same thing as {@code wait(0)}.
463 * The current thread must own this object's monitor. The thread
464 * releases ownership of this monitor and waits until either of the
465 * following two conditions has occurred:
467 * <li>Another thread notifies threads waiting on this object's monitor
468 * to wake up either through a call to the {@code notify} method
469 * or the {@code notifyAll} method.
470 * <li>The timeout period, specified by {@code timeout}
471 * milliseconds plus {@code nanos} nanoseconds arguments, has
475 * The thread then waits until it can re-obtain ownership of the
476 * monitor and resumes execution.
478 * As in the one argument version, interrupts and spurious wakeups are
479 * possible, and this method should always be used in a loop:
481 * synchronized (obj) {
482 * while (<condition does not hold>)
483 * obj.wait(timeout, nanos);
484 * ... // Perform action appropriate to condition
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
492 * @param timeout the maximum time to wait in milliseconds.
493 * @param nanos additional time, in nanoseconds range
495 * @exception IllegalArgumentException if the value of timeout is
496 * negative or the value of nanos is
497 * not in the range 0-999999.
498 * @exception IllegalMonitorStateException if the current thread is not
499 * the owner of this 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.
506 public final void wait(long timeout, int nanos) throws InterruptedException {
508 throw new IllegalArgumentException("timeout value is negative");
511 if (nanos < 0 || nanos > 999999) {
512 throw new IllegalArgumentException(
513 "nanosecond timeout value out of range");
516 if (nanos >= 500000 || (nanos != 0 && timeout == 0)) {
524 * Causes the current thread to wait until another thread invokes the
525 * {@link java.lang.Object#notify()} method or the
526 * {@link java.lang.Object#notifyAll()} method for this object.
527 * In other words, this method behaves exactly as if it simply
528 * performs the call {@code wait(0)}.
530 * The current thread must own this object's monitor. The thread
531 * releases ownership of this monitor and waits until another thread
532 * notifies threads waiting on this object's monitor to wake up
533 * either through a call to the {@code notify} method or the
534 * {@code notifyAll} method. The thread then waits until it can
535 * re-obtain ownership of the monitor and resumes execution.
537 * As in the one argument version, interrupts and spurious wakeups are
538 * possible, and this method should always be used in a loop:
540 * synchronized (obj) {
541 * while (<condition does not hold>)
543 * ... // Perform action appropriate to condition
546 * This method should only be called by a thread that is the owner
547 * of this object's monitor. See the {@code notify} method for a
548 * description of the ways in which a thread can become the owner of
551 * @exception IllegalMonitorStateException if the current thread is not
552 * the owner of the object's monitor.
553 * @exception InterruptedException if any thread interrupted the
554 * current thread before or while the current thread
555 * was waiting for a notification. The <i>interrupted
556 * status</i> of the current thread is cleared when
557 * this exception is thrown.
558 * @see java.lang.Object#notify()
559 * @see java.lang.Object#notifyAll()
561 public final void wait() throws InterruptedException {
566 * Called by the garbage collector on an object when garbage collection
567 * determines that there are no more references to the object.
568 * A subclass overrides the {@code finalize} method to dispose of
569 * system resources or to perform other cleanup.
571 * The general contract of {@code finalize} is that it is invoked
572 * if and when the Java<font size="-2"><sup>TM</sup></font> virtual
573 * machine has determined that there is no longer any
574 * means by which this object can be accessed by any thread that has
575 * not yet died, except as a result of an action taken by the
576 * finalization of some other object or class which is ready to be
577 * finalized. The {@code finalize} method may take any action, including
578 * making this object available again to other threads; the usual purpose
579 * of {@code finalize}, however, is to perform cleanup actions before
580 * the object is irrevocably discarded. For example, the finalize method
581 * for an object that represents an input/output connection might perform
582 * explicit I/O transactions to break the connection before the object is
583 * permanently discarded.
585 * The {@code finalize} method of class {@code Object} performs no
586 * special action; it simply returns normally. Subclasses of
587 * {@code Object} may override this definition.
589 * The Java programming language does not guarantee which thread will
590 * invoke the {@code finalize} method for any given object. It is
591 * guaranteed, however, that the thread that invokes finalize will not
592 * be holding any user-visible synchronization locks when finalize is
593 * invoked. If an uncaught exception is thrown by the finalize method,
594 * the exception is ignored and finalization of that object terminates.
596 * After the {@code finalize} method has been invoked for an object, no
597 * further action is taken until the Java virtual machine has again
598 * determined that there is no longer any means by which this object can
599 * be accessed by any thread that has not yet died, including possible
600 * actions by other objects or classes which are ready to be finalized,
601 * at which point the object may be discarded.
603 * The {@code finalize} method is never invoked more than once by a Java
604 * virtual machine for any given object.
606 * Any exception thrown by the {@code finalize} method causes
607 * the finalization of this object to be halted, but is otherwise
610 * @throws Throwable the {@code Exception} raised by this method
612 protected void finalize() throws Throwable { }