A Future represents the result of an asynchronous operation. When created, it probably doesn't have any result data. When the operation finishes, the Future gets the result. An application can call a Future object's get_result() method; if the result has arrived, the method returns it; otherwise, it waits for the result to arrive and then returns it.

• Instance Methods
  • check_success()
  • done()
  • get_exception()
  • get_result()
  • get_traceback()
  • wait()
• Class Methods
  • wait_all()
  • wait_any()

Instance Methods

check_success()

Check to see if the operation succeeded. Waits if necessary. Raises an exception if there was a problem; returns None if there was no problem.

done()

Returns True if the result (or exception) has arrived; otherwise, returns False. This function does not wait.

get_exception()

Waits if necessary; then returns the exception (or None if there was no exception). Returns the exception, doesn't raise it.

get_result()

Waits if necessary; then returns the result or raises the exception.

get_traceback()

Waits if necessary; then returns the exception's traceback object (or None if there was no traceback object). Python's traceback module has functions to print and work with traceback objects.

wait()

Waits until a result or exception arrives. Always returns None.

Class Methods

wait_all(futures)

Wait until all Futures in the passed list are done.

Arguments

futures

List of Future objects.

Returns None.

wait_any(futures)

Wait until at least one of a list of Futures is done.

Arguments

futures

List of Future objects.

Returns one Future that is done. (Returns None if the futures list is empty.)