BaseObject

The main objects in defcon all subclass these objects.

See also

NotificationCenter
The base object uses notifications to notify observers about changes. The API for subscribing/unsubscribing to notifications are detailed below. Some familiarity with the NotificationCenter might be helpful.

BaseObject

class defcon.objects.base.BaseObject

The base object in defcon from which all other objects should be derived.

This object posts the following notifications:

  • BaseObject.Changed
  • BaseObject.BeginUndo
  • BaseObject.EndUndo
  • BaseObject.BeginRedo
  • BaseObject.EndRedo

Keep in mind that subclasses will not post these same notifications.

Subclasses must override the following attributes:

Name Notes
changeNotificationName This must be a string unique to the class indicating the name of the notification to be posted when the dirty attribute is set.
representationFactories This must be a dictionary that is shared across all instances of the class.
addObserver(observer, methodName, notification)

Add an observer to this object’s notification dispatcher.

  • observer An object that can be referenced with weakref.
  • methodName A string representing the method to be called when the notification is posted.
  • notification The notification that the observer should be notified of.

The method that will be called as a result of the action must accept a single notification argument. This will be a defcon.tools.notifications.Notification object.

This is a convenience method that does the same thing as:

dispatcher = anObject.dispatcher
dispatcher.addObserver(observer=observer, methodName=methodName,
    notification=notification, observable=anObject)
canRedo()

Returns a boolean indicating whether the undo manager is able to perform a redo.

canUndo()

Returns a boolean indicating whether the undo manager is able to perform an undo.

destroyAllRepresentations(notification=None)

Destroy all representations.

destroyRepresentation(name, **kwargs)

Destroy the stored representation for name and **kwargs. If no kwargs are given, any representation with name will be destroyed regardless of the kwargs passed when the representation was created.

dirty

The dirty state of the object. True if the object has been changed. False if not. Setting this to True will cause the base changed notification to be posted. The object will automatically maintain this attribute and update it as you change the object.

disableNotifications(notification=None, observer=None)

Disable this object’s notifications until told to resume them.

  • notification The specific notification to disable. This is optional. If no notification is given, all notifications will be disabled.

This is a convenience method that does the same thing as:

dispatcher = anObject.dispatcher
dispatcher.disableNotifications(
    observable=anObject, notification=notification, observer=observer)
dispatcher

The defcon.tools.notifications.NotificationCenter assigned to the parent of this object.

enableNotifications(notification=None, observer=None)

Enable this object’s notifications.

  • notification The specific notification to enable. This is optional.

This is a convenience method that does the same thing as:

dispatcher = anObject.dispatcher
dispatcher.enableNotifications(
    observable=anObject, notification=notification, observer=observer)
getDataForSerialization(**kwargs)

Return a dict of data that can be pickled.

getRepresentation(name, **kwargs)

Get a representation. name must be a registered representation name. **kwargs will be passed to the appropriate representation factory.

hasCachedRepresentation(name, **kwargs)

Returns a boolean indicating if a representation for name and **kwargs is cached in the object.

hasObserver(observer, notification)

Returns a boolean indicating is the observer is registered for notification.

This is a convenience method that does the same thing as:

dispatcher = anObject.dispatcher
dispatcher.hasObserver(observer=observer,
    notification=notification, observable=anObject)
holdNotifications(notification=None, note=None)

Hold this object’s notifications until told to release them.

  • notification The specific notification to hold. This is optional. If no notification is given, all notifications will be held.
  • note An arbitrary string containing information about why the hold has been requested, the requester, etc. This is used for reference only.

This is a convenience method that does the same thing as:

dispatcher = anObject.dispatcher
dispatcher.holdNotifications(
    observable=anObject, notification=notification, note=note)
postNotification(notification, data=None)

Post a notification through this object’s notification dispatcher.

  • notification The name of the notification.
  • data Arbitrary data that will be stored in the Notification object.

This is a convenience method that does the same thing as:

dispatcher = anObject.dispatcher
dispatcher.postNotification(
    notification=notification, observable=anObject, data=data)
redo()

Perform a redo if possible, or return. If redo is performed, this will post BaseObject.BeginRedo and BaseObject.EndRedo notifications.

releaseHeldNotifications(notification=None)

Release this object’s held notifications.

  • notification The specific notification to hold. This is optional.

This is a convenience method that does the same thing as:

dispatcher = anObject.dispatcher
dispatcher.releaseHeldNotifications(
    observable=anObject, notification=notification)
removeObserver(observer, notification)

Remove an observer from this object’s notification dispatcher.

  • observer A registered object.
  • notification The notification that the observer was registered to be notified of.

This is a convenience method that does the same thing as:

dispatcher = anObject.dispatcher
dispatcher.removeObserver(observer=observer,
    notification=notification, observable=anObject)
representationKeys()

Get a list of all representation keys that are currently cached.

setDataFromSerialization(data)

Restore state from the provided data-dict.

undo()

Perform an undo if possible, or return. If undo is performed, this will post BaseObject.BeginUndo and BaseObject.EndUndo notifications.

undoManager

The undo manager assigned to this object.

BaseDictObject

class defcon.objects.base.BaseDictObject

A subclass of BaseObject that implements a dict API. Any changes to the contents of the object will cause the dirty attribute to be set to True.