Stéphane Ducasse a écrit :
> sounds cool.
> For me the most important aspect is that preferenceCollector (our
> current preference class should be a removable layer on top
> of the system that are declaring preference.
>
> Is is correct that
>
> PreferenceCollector whenChanged: #gradientButtonLook inClass:
> PrefProvider notify: self using: #gradientButtonLookIsNow: .
>
> means that PrefProvider will receive the message
> gradientButtonLookIsNow:
no, but see the code below:
-----------
PrefListener>>initialize
super initialize.
PreferenceCollector whenChanged: #gradientButtonLook inClass:
PrefProvider notify: self using: #gradientButtonLookIsNow: .
-----------
it means that a PrefListener instance will receive the
#gradientButtonLookIsNow: message each time the preference
#gradientButtonLook defined in class PrefProvider is changed.
PrefListener and PrefProvider represent can be any class in the system.
So, in order to read a preference value an object get it from the
provider class by message sending,
the provider is a class in a package which defines preferences (no need
for PreferenceCollector to get the preference value).
>
> This way we can push preference to the tools
yes
> and thety do not have to query the information in the Collector at
> run-time
yes,
Each package have its own preference set in it represented by a set of
methods with pragma.
When such a package is loaded, its preferences are automatically stored
by PreferenceCollector.
When a package is removed, its preferences are automatically removed
from PreferenceCollector.
PreferenceCollector is only here for supporting tools (cool UI ...) and
for change notifications.
> (hence we could remove Preference and have a more OO design).
I guess yes.
>
> Sorry not to reply earlier (I was breaking yet another wall in our
> "kitchen")
bon courage :)
alain
>
> Stef
>
>
> On Mar 1, 2009, at 10:05 AM, Alain Plantec wrote:
>
>> Hi all,
>>
>> joined Zoo package is a attempt to translate in code what we
>> discussed here before about preference refactoring.
>>
>> The framework is made of 3 classes: PreferenceCollector,
>> PreferenceDefinition and PreferenceValue.
>> In Zoo there are also 2 classes for testing: PrefProvider and
>> PrefChangeListener.
>> PrefProvider class declares some preferences and PrefChangeListener
>> is here to test preference change notification.
>>
>> PrefChangeListener>>initialize
>> super initialize.
>> PreferenceCollector whenChanged: #gradientButtonLook inClass:
>> PrefProvider notify: self using: #gradientButtonLookIsNow: .
>> PreferenceCollector whenChanged: #gradientButtonLook inClass:
>> PrefProvider notify: self using: #gradientLook:
>>
>> PrefChangeListener class>>test
>> "self test"
>> PrefChangeListener new inspect.
>> PrefProvider gradientButtonLook: PrefProvider gradientButtonLook
>> value not.
>> PrefProvider gradientButtonLook: PrefProvider gradientButtonLook
>> value not.
>> PrefProvider gradientButtonLook: PrefProvider gradientButtonLook
>> value not.
>>
>>
>> From PreferenceCollector comment:
>> --------------------------------------
>> A PreferenceCollector automatically collects all preferences.
>> A preference is represented by a PreferenceDefinition.
>> All PreferenceDefinition are stored in the preferences instance
>> variable.
>>
>> Instance Variables
>> preferences: OrderedCollection of PreferenceDefinition
>>
>> preferences
>> - contains all PreferenceDefinition which are automatically built
>> from pragma found in preference getters
>>
>>
>> ADDING A PREFERENCE
>> PreferenceCollector makes use of the SystemChangeNotifier in order to
>> automate the adding, the removing and the updating of preferences.
>> See #PreferenceCollector>>event: to see how preferences update is
>> implemented.
>>
>> Editing a new method with a preference pragma or inserting a
>> preference pragma in an existing method are
>> the two ways for preference definition adding.
>> The only way to remove a preference definition is to remove the
>> corresponding method.
>>
>> Example of a "blackAndWhite" preference.
>> Methods below are defined by the preference provider
>> APreferencePrivider class.
>> Note that the value stored in BlackAndWhite class variable is an
>> instance of PreferenceValue.
>> In this example, the default value is directly given with the pragma:
>> -------------
>> APreferencePrivider class>>blackAndWhite
>> <preference: 'Use black and white' type: #Boolean set:
>> #blackAndWhite: defaultValue: false description: 'Use black and white'>
>> ^ BlackAndWhite
>> ifNil: [BlackAndWhite := PreferenceValue value: false location:
>> self selector: #blackAndWhite]
>>
>> APreferencePrivider class>>blackAndWhite: aBoolean
>> self blackAndWhite value: aBoolean
>> -------------
>>
>> If a default value can't be specified in the pragma, another way
>> consists in using a selector which
>> represents the message to send to the class in order to get the
>> default value:
>>
>> -------------
>> APreferencePrivider class>>standardFont
>> <preference: 'The default system font' type: #LogicalFont set:
>> #standardFont: default: #defaultStandardFont description: 'The
>> default system font'>
>> ^ StandardFont
>> ifNil: [StandardFont := PreferenceValue value: self
>> defaultStandardFont location: self selector: #standardFont]
>>
>> APreferencePrivider class>>standardFont: aFont
>> self standardFont value: aFont
>> APreferencePrivider class>>defaultStandardFont
>> ^ LogicalFont
>> familyName: 'Arial'
>> fallbackFamilyNames: nil
>> pointSize: 12
>> stretchValue: 5
>> weightValue: 400
>> slantValue: 0
>> -------------
>>
>> LISTENING TO A PREFERENCE VALUE CHANGE
>> Any object can register itself as a preference value change listener.
>> See #PreferenceCollector class>>whenChanged: inClass:notify:using:.
>>
>> Each time a preference value is changed, #preference:
>> inClass:changedWith: is sent to the PreferenceCollector class.
>>
>> Example of code a listener can implement in order to be notified each
>> time a gradientButtonLook preference defined by a PrefProvider class
>> is changed.
>> In this example, the listener ask to be notified by a send of
>> #gradientButtonLookIsNow: message.
>> The argument given to gradientButtonLookIsNow: is the new preference
>> value.
>> -------------
>> ....
>> PreferenceCollector whenChanged: #gradientButtonLook inClass:
>> PrefProvider notify: self using: #gradientButtonLookIsNow:.
>> ....
>> -------------
>>
>> What do you think ?
>>
>> cheers
>> Alain
>>
>>
>> <Zoo-alain_plantec.10.mcz>_______________________________________________
>>
>> Pharo-project mailing list
>> [email protected]
>> http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project
>
>
>
_______________________________________________
Pharo-project mailing list
[email protected]
http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project
