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