Events

An Event is a change in system state. harami implements Events as a combination of an @event decorator applied to an Event Source. An Event Source is a function or method that the generator of an event will use to raise an event. For example, a network analyzer might raise an event to signal a change in network availability. An Event Handler receives the args passed to an Event Source, and is typically implemented as a function or method that receives sender (the object that raised the event) and EventArgs (the args used to raise the event.)

Decorators

@event

Decorates a function or method as an Event Source.

Example (functions):

from harami import event

@event
def on_state_changed(state: any):
    pass
on_state_changed += lambda s,e: print(f'New State: {e.args}')
on_state_changed('Hello, World!')
# outputs to console
# New State: ['Hello, World!']

Example (methods):

from harami import event

class Foo:
    @event
    def on_state_changed(self, state:Any):
        pass

class Bar:
    def __init__(self, foo:Foo) -> None:
        self.__foo = foo
        self.__foo.on_state_changed += self.__my_event_handler
    def __my_event_handler(self: object, e: EventArgs) -> None:
        print(f'New State: {e.args})

foo = Foo()
bar = Bar(foo)
foo.on_state_changed('Hello, World!')
# outputs to console
# New State: ['Hello, World!']