Appliance

Appliances are entities which group together behavioural rules.

Appliances are abstract non deterministic state machines, they do not know how to turn on your light, they just know that your light should be turned on.

Events are notified to Appliances and can make transit the state machine.

Tip

The Appliance state machine can be modified by a user at any time.

Event processing, inside an Appliance instance, can be disabled/enabled (you can see them grayed out in the example projects).

If, as an example, you have a curtain model automated to be opened by the system when it receives the event home.event.sleepiness.Event.Awake, meaning the user has to be wake up, then the user can inhibit the processing of such an event every time he does not want to be wake up.

Appliances states are designed to be easily reusable.

When writing the state machine one of the most difficult things is to be sure that every transition is correct. For this reason the behaviour of an Appliance is tested and described by a BDD test.

• State
  • From Forced States to other States
    • Example
  • Event Class
  • Callable Class
  • State Class

Appliance Class

class home.Appliance(name: str, events: Iterable[home.Event] = None, events_disabled: Iterable[home.Event] = None)

An abstract representation of a device. An appliance has a state which is changed by notified events.

property name: str

The Appliance name

property events: Iterable[home.Event]

A list of Events already notified to the Appliance

property events_disabled: Iterable[home.Event]

A list of Events disabled in the Appliance state machine

property state: home.appliance.State

The Appliance state

property forced_enum: home.Event

An Event capable of making the Appliance forced (if any)

update(other: home.Appliance) → Tuple[home.appliance.State, home.appliance.State]

Update state using events taken from another Appliance

Parameters

other – look for new events in another Appliance and use them to update Appliance state

Returns

(old_state, new_state) a tuple with the old state, the state before updating, and the new state, the one after the update.

update_by(trigger: home.protocol.Trigger, description: home.protocol.Description) → Tuple[home.appliance.State, home.appliance.State]

Update state using trigger. A trigger is capable of creating a new state using its method make_new_state_from.

Parameters

• trigger – a trigger capable of making a new state from an old one.

• description – a message description taken from a bus event, it carries updated data used to make the new state

Returns

(old_state, new_state) a tuple with the old state, the state before updating, and the new state, the one after the update.

notify(event: home.Event) → Tuple[home.appliance.State, home.appliance.State]

Notify a new event to the Appliance

Parameters

event – an event

Returns

(old_state, new_state) a tuple with the old state, the state before notifying event, and the new state, the one after the notify.

is_notified(event: home.Event) → bool

Event has been notified to the Appliance?

Parameters

event – an event

Returns

bool

is_enabled(event: home.Event) → bool

Events of the same given type are enabled in the state machine?

Parameters

event – an event

Returns

bool

enable(event: home.Event)

Enable events of the same given type in the state machine

Parameters

event – an event

Returns

bool

disable(event: home.Event)

Disable events of the same given type in the state machine

Parameters

event – an event

Returns

bool