Class implementing event objects. Events manage a flag that can be set to true with the set() method and reset to false with the clear() method. The wait() method blocks until the flag is true. The flag is initially false.
| 549 | |
| 550 | |
| 551 | class Event: |
| 552 | """Class implementing event objects. |
| 553 | |
| 554 | Events manage a flag that can be set to true with the set() method and reset |
| 555 | to false with the clear() method. The wait() method blocks until the flag is |
| 556 | true. The flag is initially false. |
| 557 | |
| 558 | """ |
| 559 | |
| 560 | # After Tim Peters' event class (without is_posted()) |
| 561 | |
| 562 | def __init__(self): |
| 563 | self._cond = Condition(Lock()) |
| 564 | self._flag = False |
| 565 | |
| 566 | def __repr__(self): |
| 567 | cls = self.__class__ |
| 568 | status = 'set' if self._flag else 'unset' |
| 569 | return f"<{cls.__module__}.{cls.__qualname__} at {id(self):#x}: {status}>" |
| 570 | |
| 571 | def _at_fork_reinit(self): |
| 572 | # Private method called by Thread._reset_internal_locks() |
| 573 | self._cond._at_fork_reinit() |
| 574 | |
| 575 | def is_set(self): |
| 576 | """Return true if and only if the internal flag is true.""" |
| 577 | return self._flag |
| 578 | |
| 579 | def isSet(self): |
| 580 | """Return true if and only if the internal flag is true. |
| 581 | |
| 582 | This method is deprecated, use is_set() instead. |
| 583 | |
| 584 | """ |
| 585 | import warnings |
| 586 | warnings.warn('isSet() is deprecated, use is_set() instead', |
| 587 | DeprecationWarning, stacklevel=2) |
| 588 | return self.is_set() |
| 589 | |
| 590 | def set(self): |
| 591 | """Set the internal flag to true. |
| 592 | |
| 593 | All threads waiting for it to become true are awakened. Threads |
| 594 | that call wait() once the flag is true will not block at all. |
| 595 | |
| 596 | """ |
| 597 | with self._cond: |
| 598 | self._flag = True |
| 599 | self._cond.notify_all() |
| 600 | |
| 601 | def clear(self): |
| 602 | """Reset the internal flag to false. |
| 603 | |
| 604 | Subsequently, threads calling wait() will block until set() is called to |
| 605 | set the internal flag to true again. |
| 606 | |
| 607 | """ |
| 608 | with self._cond: |