AccessEngine :: AEState :: Setting :: Setting :: Class Setting

Class Setting

object --+
         |
        Setting

A wrapper around a value with a strict type in a AEState.AEState object. Provides a label and longer description of the value. Has a flag indicating whether the value should be persisted or not. Defines methods for caching the current value and restoring it later. Supports the observer pattern to notify listeners of changes to the value.

All instance variables should be considered public readable except for those prefixed with an underscore. The value property should also be considered public writable. value is a property which will correctly notify observers when changed.

Subclasses may define new value properties that perform conversions or do other tasks. The data retrieved via the value property must always be the data that should be persisted to disk for a setting.

Instance Methods

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__init__(self, state, name, default, label, description, persist)
Initializes all instance variables.

source code

update(self, setting)
Updates this setting with the default value and current value of another setting of the same kind.

source code

Setting

copy(self)
Makes a shallow copy of this object.

source code

object

_getValue(self)
Gets the value.

source code

_setValue(self, val)
Sets the value and notifies all observers only if the new value is different from the old.

source code

_notify(self)
Notifies all observers of a change in value.

source code

addObserver(self, ob, *args)
Stores a weak reference to the observer to be notified when the value of this setting changes.

source code

removeObserver(self, ob)
Removes a weak reference to the observer.

source code

clearObservers(self)
Remove all observers.

source code

save(self)
Caches the current value for later restoration.

source code

restore(self)
Restores the cached value.

source code

object

serialize(self)
Gets the current _value as the data to serialize.

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unserialize(self, val)
Sets the current _value from data that was unserialized.

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Inherited from object: __delattr__, __getattribute__, __hash__, __new__, __reduce__, __reduce_ex__, __repr__, __setattr__, __str__

Class Variables

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value = property(_getValue, _setValue)

Instance Variables

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object

_cached
Cached value from the last save invocation

dictionary

_observers
Callables to notify on a value change mapped to their arguments

object

_value
Arbitrary protected value of this setting.

object

default
Default value of the setting

string

description
Extended description of the setting

string

label
Label of the setting

string

name
Name of the setting

boolean

persist
Should this setting value be persisted to disk?

weakref.proxy to AEState.AEState

state
Object in which this setting resides

Properties

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Inherited from object: __class__

Method Details

[hide private]

init(self, state, name, default, label, description, persist)
(Constructor)

source code

Initializes all instance variables.

Overrides: object.__init__

update(self, setting)

source code

Updates this setting with the default value and current value of another setting of the same kind.

Parameters:

setting (Setting) - Setting of the same kind as this one

copy(self)

source code

Makes a shallow copy of this object.

Returns: Setting: Shallow copy of this setting

_getValue(self)

source code

Gets the value.

Returns: object: Current value of the setting

_setValue(self, val)

source code

Sets the value and notifies all observers only if the new value is different from the old.

Parameters:

val (object) - New value to store in the setting

_notify(self)

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Notifies all observers of a change in value. If an observer is dead, as indicated by a ReferenceError, removes it from the list of observers.

addObserver(self, ob, *args)

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Stores a weak reference to the observer to be notified when the value of this setting changes. Bound methods will work as observers.

Additional arguments will be passed to the observer on notification. Weak reference proxies to arguments will be used whenever possible to avoid inhibiting garbage collection.

Parameters:

ob (callable) - The observer

Note: Because weak references are used, a reference may be dead when it is later delivered to an observer. The observer may safely ignore this error as it will be caught by the _notify method. Notification will cease immediately as soon as the first ReferenceError is encountered.

removeObserver(self, ob)

source code

Removes a weak reference to the observer. Pass a strong reference to the observer to remove, not a weak reference.

Parameters:

ob (callable) - The observer

Raises:

KeyError - When the given callable is not an observer of this setting

save(self)

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Caches the current value for later restoration. Only one value may be cached at a time. It's a box, not a stack.

restore(self)

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Restores the cached value. Sends notification only if the value in the cache is different from the current value.

serialize(self)

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Gets the current _value as the data to serialize. This default implementation bypasses the property fget method.

Returns: object: Data value to serialize

unserialize(self, val)

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Sets the current _value from data that was unserialized. This default implementation bypasses the property fset method.

Parameters:

val (object) - Data value to store

Class Setting

__init__(self, state, name, default, label, description, persist) (Constructor)

update(self, setting)

copy(self)

_getValue(self)

_setValue(self, val)

_notify(self)

addObserver(self, ob, *args)

removeObserver(self, ob)

save(self)

restore(self)

serialize(self)

unserialize(self, val)

init(self, state, name, default, label, description, persist)
(Constructor)