rubycocoa-talk

[Rubycocoa-talk] RubyCocoa, CoreData, & NSPersistentDocumentTutorial

[Rupert B. <rup...@li...>]

Hi,

I am using today's latest CVS version of RubyCocoa, and trying  
coredata and kvc_depends_on : great !
I am trying to "translate" the NSPersistentDocumentTutorial into Ruby :
     http://developer.apple.com/documentation/Cocoa/Conceptual/ 
NSPersistentDocumentTutorial

I have got to chapter 3 (creating the custome Employee class) : this  
works with Employee.rb, I have even got fullNameAndID working,  
dynamically computed from firstName and lastName, and displayed in  
the GUI.
However, I do not seem to be able to connect firstName in the GUI  
with the model in Employee.rb; ditto for lastName. This is my  
Employee class :

class Employee < OSX::NSManagedObject
     include OSX

     attr_accessor :firstName
     attr_accessor :lastName

     kvc_accessor :lastName, :firstName
     kvc_depends_on([ :lastName, :firstName], :fullNameAndID)

     def initialize
         @firstName = "MyFirst"
         @lastName  = "MyLast"
     end

     def fullNameAndID
         return OSX::NSString.stringWithString(@lastName + ", " +  
@firstName)
     end

end

What am I missing ?  Is there something not obvious which should be  
done, considering that this tutorial uses bindings (of course) ad  
core data (including a data model with entities) ?

Thanks for any help,
Rup

Re: [Rubycocoa-talk] RubyCocoa, CoreData, & NSPersistentDocumentTutorial

[Jonathan P. <jp...@dc...>]

On 3 Nov 2005, at 21:31, Rupert Barrow wrote:

> I have got to chapter 3 (creating the custome Employee class) :  
> this works with Employee.rb, I have even got fullNameAndID working,  
> dynamically computed from firstName and lastName, and displayed in  
> the GUI.
> However, I do not seem to be able to connect firstName in the GUI  
> with the model in Employee.rb; ditto for lastName. This is my  
> Employee class :

I'm not entirely sure from your description what the problem you're  
having is. However, I do notice a problem with your code that may be  
related:

> class Employee < OSX::NSManagedObject
>     include OSX
>
>     attr_accessor :firstName
>     attr_accessor :lastName
>
>     kvc_accessor :lastName, :firstName
>     kvc_depends_on([ :lastName, :firstName], :fullNameAndID)
>
>     def initialize
>         @firstName = "MyFirst"
>         @lastName  = "MyLast"
>     end
>

[Let me say first that I've not used Core Data yet, so this is my  
understanding from glancing over the documentation. Please correct  
any misunderstanding!]

Since you're using Core Data, all the data members of the class are  
already managed for you. Therefore, you should not define firstName  
and lastName as accessors, nor should you use ruby @firstName/ 
@lastName variables.

Instead, just access firstName etc as if it were already defined as  
an accessor (or perhaps you need to use setValue:forKey: and  
valueForKey:). RubyCocoa will forward the call through to Objective  
C, where Core Data will handle the request for you.


Hope that is of some help,
Jonathan

Re: [Rubycocoa-talk] RubyCocoa, CoreData, & NSPersistentDocumentTutorial

[kimura w. <ki...@us...>]

Hi,

I'm trying this tutorial.


Thu, 3 Nov 2005 23:13:03 +0000, Jonathan Paisley wrote:
>On 3 Nov 2005, at 21:31, Rupert Barrow wrote:
>

>Since you're using Core Data, all the data members of the class are  
>already managed for you. Therefore, you should not define firstName  
>and lastName as accessors, nor should you use ruby @firstName/ 
>@lastName variables.
>
>Instead, just access firstName etc as if it were already defined as  
>an accessor (or perhaps you need to use setValue:forKey: and  
>valueForKey:). RubyCocoa will forward the call through to Objective  
>C, where Core Data will handle the request for you.
>

It's right. To access attributes of an Employee, we have to use 
setValue:forKey and valueForKey:. 

for example:
------------
  def fullNameAndID
    return OSX::NSString.stringWithString(valueForKey("lastName").to_s + 
           ", " +  valueForKey("firstName").to_s)
  end
------------


I felt that was not smart. I defined a method "kvc_wrapper". This method 
defines accessors wrapping "valueForKey:" and "setValue:forKey:".
# tell me a better name of "kvc_wrapper", please.

my Employee.rb:
---------------
require 'osx/cocoa'
require 'osx/coredata'

# add kvc_wrapper
module OSX

  module NSKVCBehaviorAttachment

    # accessor for keys defined in Cocoa
    def kvc_wrapper(*keys)
      keys.each do |key|
        class_eval <<-EOE_KVC_WRAPPER,__FILE__,__LINE__+1
        def #{key}
          valueForKey("#{key}")
        end
        def #{key}=(val)
          setValue_forKey(val, "#{key}")
        end
        EOE_KVC_WRAPPER
      end
    end
  
  end

end

# Employee class 
class Employee < OSX::NSManagedObject
  
  kvc_depends_on [:lastName, :firstName], :fullNameAndID

  # define wrappers
  kvc_wrapper :lastName, :firstName, :employeeID 

  def fullNameAndID
    sprintf('%s, %s (%d)', lastName.to_s, firstName.to_s, employeeID)
  end
  
end
---------------


I think that is possible to define wrappers automatically from 
NSManagedObjectModel#entities -> NSEntityDescription, but I do not
know how to implement.



-- 
kimura wataru

Re: [Rubycocoa-talk] RubyCocoa, CoreData, & NSPersistentDocumentTutorial

[kimura w. <ki...@us...>]

Hi,

I added some changes to CVS. This changes enables automated wrapping
of Key-Value Coding accessors. When you define a subclass of 
NSManagedObject, RubyCocoa defines wrappers to attributes and 
relationships from CoreData models.

my Employee.rb at chapter 3.
-------------
require 'osx/cocoa'
require 'osx/coredata'

class Employee < OSX::NSManagedObject
  
  kvc_depends_on [:lastName, :firstName], :fullNameAndID

  @@temp_id = 0
  
  def fullNameAndID
    sprintf('%s, %s (%d)', lastName.to_s, firstName.to_s, employeeID)
  end
  
  ns_overrides :awakeFromInsert
  def awakeFromInsert
    @@temp_id += 1
    self.employeeID = OSX::NSNumber.numberWithInt(@@temp_id)
  end
  
end
-------------

A new module function OSX::CoreData.define_wrapper() is core of the 
feature.

Fri, 04 Nov 2005 20:21:09 +0900, kimura wataru wrote:
>Hi,
>
>I'm trying this tutorial.
>

>I think that is possible to define wrappers automatically from 
>NSManagedObjectModel#entities -> NSEntityDescription, but I do not
>know how to implement.
>


-- 
kimura wataru

Re: [Rubycocoa-talk] RubyCocoa, CoreData, & NSPersistentDocumentTutorial

[Rupert B. <rup...@fr...>]

OK, here is the final results of the experiment.
With this code ...

class Employee < OSX::NSManagedObject
	include OSX
=09
	@@lastID =3D 123

	kvc_accessor :lastName, :firstName, :employeeID
	kvc_depends_on([ :lastName, :firstName, :employeeID ], =
:fullNameAndID)

	def initialize
		rbSetValue_forKey(NSNumber.numberWithInt(@@lastID), =
"employeeID")
		puts "*** =
rbSetValue_forKey(NSNumber.numberWithInt(@@lastID), =20
\"employeeID\") :  #{rbValueForKey("employeeID")} ***"
	end

	def fullNameAndID
		puts "*** self =3D #{self} ***"
		puts "*** rbValueForKey(\"employeeID\") =3D =
#{rbValueForKey=20
("employeeID")} ***"
	end
end

... I get the following output ...

*** rbSetValue_forKey(NSNumber.numberWithInt(@@lastID), =20
"employeeID") :  123 ***
*** self =3D <Employee: 0x557eb0> (entity: Employee; id: 0x55a950 <x-=20
coredata:///Employee/t31E6B1EE-8E9F-4E1A-BA1E-47CA62FEBF3D> ; data: {
     department =3D nil;
     directReports =3D ();
     employeeID =3D nil;
     firstName =3D First;
     lastName =3D Last;
     manager =3D nil;
     salary =3D 0;
}) ***
*** rbValueForKey("employeeID") =3D 123 ***

I am setting the employeeID correctly (through setValue), but the =20
value is not 'arriving' in the coredata object. However, it is not =20
lost, because I re-read from in another method (fullNameAndID) with =20
the valueForKey method.

Any ideas ?

Rup

Le 4 nov. 05 =C3=A0 21:32, Rupert Barrow a =C3=A9crit :

> Jonathan,
>
> Thanks for answering quickly.
>
> I removed definition of the @firstName and @lastName attributes, =20
> and it worked..
>
> After studying your answer, I noticed the following :
> '    kvc_accessor :lastName, :firstName'
> creates these methods :
> 	firstName
> 	firstName=3D
> 	lastName
> 	lastName=3D
>
> If I comment out this code, the methods disappear. When I dump =20
> Employee, I see the "attributes" :
> *** Employee =3D <Employee: 0x3ff5b0> (entity: Employee; id: 0x53f370 =20=

> <x-coredata:///Employee/tFE462E87-F74A-4826-8487-7C16DBECD891> ; =20
> data: {
>     department =3D nil;
>     directReports =3D ();
>     employeeID =3D nil;
>     firstName =3D First;
>     lastName =3D Last;
>     manager =3D nil;
>     salary =3D 0;
> }) ***
> but when I try to access them, the methods are obviously undefined :
> 2005-11-04 21:25:56.696 DepartmentAndEmployees[789] Exception =20
> raised during posting of notification.  Ignored.  exception: =20
> undefined method `lastName' for class `Employee'
>
> So :
> - kvc_depends_on declares and uses one set of accessors
> - CoreData relies on another access/update method : through =20
> setValue:forKey: and valueForKey:, as you mentioned.
>
> Would it not be nice to 'merge' them both, so as not to have to =20
> handle to access/update methods for the same data ?
>
> Rup
>
>
> Le 4 nov. 05 =C3=A0 00:13, Jonathan Paisley a =C3=A9crit :
>
>> On 3 Nov 2005, at 21:31, Rupert Barrow wrote:
>>
>>> class Employee < OSX::NSManagedObject
>>>     include OSX
>>>
>>>     attr_accessor :firstName
>>>     attr_accessor :lastName
>>>
>>>     kvc_accessor :lastName, :firstName
>>>     kvc_depends_on([ :lastName, :firstName], :fullNameAndID)
>>>
>>>     def initialize
>>>         @firstName =3D "MyFirst"
>>>         @lastName  =3D "MyLast"
>>>     end
>>>
>>
>> [Let me say first that I've not used Core Data yet, so this is my =20
>> understanding from glancing over the documentation. Please correct =20=

>> any misunderstanding!]
>>
>> Since you're using Core Data, all the data members of the class =20
>> are already managed for you. Therefore, you should not define =20
>> firstName and lastName as accessors, nor should you use ruby =20
>> @firstName/@lastName variables.
>

Re: [Rubycocoa-talk] RubyCocoa, CoreData, & NSPersistentDocumentTutorial[MESSAGE NOT SCANNED]

[Jonathan P. <jp...@dc...>]

On 4 Nov 2005, at 20:53, Rupert BARROW wrote:
>
>     kvc_accessor :lastName, :firstName, :employeeID
>     kvc_depends_on 
> ([ :lastName, :firstName, :employeeID ], :fullNameAndID)
>
>     def initialize
>         rbSetValue_forKey(NSNumber.numberWithInt(@@lastID),  
> "employeeID")
>
> I am setting the employeeID correctly (through setValue), but the  
> value is not 'arriving' in the coredata object. However, it is not  
> lost, because I re-read from in another method (fullNameAndID) with  
> the valueForKey method.

You're calling rbSetValue... rather than setValue... The rbSetValue  
method ends up just calling the ruby employeeID= method, which has  
the effect of setting the instance variable in the ruby class (look  
at the definition in oc_import.rb to understand more).

Try replacing kvc_accessor with kvc_wrapper, as defined by Kimura  
Wataru in an email earlier today in this thread. This declares the  
ruby-level accessors in terms of setValue:forKey: and valueForKey:  
which should hopefully solve the problem.

i.e.:

    kvc_wrapper :lastName, :firstName, :employeeID
    kvc_depends_on 
([ :lastName, :firstName, :employeeID ], :fullNameAndID)

    def initialize
       employeeID = @@lastID
       ...
    end

Also, since this is a Cocoa class, I'm not sure that the initialize  
method works - I think you have to override init and define it like  
in a Cocoa class. I'll try and come up with an example later if you  
think this is a problem.


Hope that helps.
Jonathan

Re: [Rubycocoa-talk] RubyCocoa, CoreData, & NSPersistentDocumentTutorial

[Rupert B. <rup...@fr...>]

Le 4 nov. 05 =C3=A0 22:04, Jonathan Paisley a =C3=A9crit :

> On 4 Nov 2005, at 20:53, Rupert BARROW wrote:
>
> Try replacing kvc_accessor with kvc_wrapper, as defined by Kimura =20
> Wataru in an email earlier today in this thread.

Sorry, I'm on a 'digest' mail subscription to the list, so I missed =20
your post, Kimura-San.

> This declares the ruby-level accessors in terms of setValue:forKey: =20=

> and valueForKey: which should hopefully solve the problem.
>
> i.e.:
>
>    kvc_wrapper :lastName, :firstName, :employeeID
>    kvc_depends_on=20
> ([ :lastName, :firstName, :employeeID ], :fullNameAndID)
>
>    def initialize
>       employeeID =3D @@lastID
>       ...
>    end

Great, thanks to both of you, things are now working, but not =20
*exactly* as you mention.
In my 'awakeFromInsert' method, why does

	employeeID =3D 123		# not self.employeeID
	puts employeeID
	puts self

reply '123' for employeeID, but NOT update self :
<Employee: 0x520d00> (entity: Employee; id: 0x523ed0 <x-coredata:///=20
Employee/tFC895DBA-B5E8-4764-B296-32FA106D280E> ; data: {
     department =3D nil;
     directReports =3D ();
     employeeID =3D nil;			# not updated
     firstName =3D First;
     lastName =3D Last;
     manager =3D nil;
     salary =3D 0;
})

when
	self.employeeID =3D 123	# using self.employeeID
	puts employeeID
	puts self
replies '123' for employeeID AND updates CORRECTLY self ?
<Employee: 0x520d00> (entity: Employee; id: 0x523ed0 <x-coredata:///=20
Employee/tFC895DBA-B5E8-4764-B296-32FA106D280E> ; data: {
     department =3D nil;
     directReports =3D ();
     employeeID =3D 123;			# updated correctly
     firstName =3D First;
     lastName =3D Last;
     manager =3D nil;
     salary =3D 0;
})

Thanks for your help. Being rather newbie on Cocoa/CoreData and =20
RubyCocoa, I do not know whether I am using incorrectly the former or =20=

the latter.

Cheers,
Rup=

Re: [Rubycocoa-talk] RubyCocoa, CoreData, & NSPersistentDocumentTutorial[MESSAGE NOT SCANNED]

[Jonathan P. <jp...@dc...>]

>     employeeID = 123        # not self.employeeID
>     puts employeeID
>     puts self

>     self.employeeID = 123    # using self.employeeID
>     puts employeeID
>     puts self

Ah, my fault for getting this wrong in my earlier message.

Ruby assumes 'employeeID = 123' is a local variable assignment.  
Hence, the 'puts employeeID' simply retrieves the local variable  
assigned on the preceding line. CoreData or RubyCocoa are never  
involved.

In your second example, the first line directly calls the setter  
(self.employeeID=) and the second line indirectly calls the getter  
(self.employeeID) since no local variable with that name (employeeID)  
has been defined yet.

Hope that makes sense. Glad to hear that things are beginning to work.

Jonathan

Re: [Rubycocoa-talk] RubyCocoa, CoreData, & NSPersistentDocumentTutorial[MESSAGE NOT SCANNED]

[Rupert B. <rup...@fr...>]

Le 5 nov. 05 =C3=A0 00:22, Jonathan Paisley a =C3=A9crit :

>>     employeeID =3D 123        # not self.employeeID
>>     puts employeeID
>>     puts self
>
>>     self.employeeID =3D 123    # using self.employeeID
>>     puts employeeID
>>     puts self
>
> Ah, my fault for getting this wrong in my earlier message.
>
> Ruby assumes 'employeeID =3D 123' is a local variable assignment.

Of course !
Gee, I'm getting tired.  I'm moving on to chapter 4 ...

Thanks again,
Rup