Pierce T. Wetter III
pierc****@twinf*****
Thu Apr 12 03:26:34 JST 2007
So the problem I was having was that my accessor methods written
in ruby weren't getting called.
I figured this was because oc_import.rb:502 was discarding them,
called from cocoa_macros.rb:102
So I commented them out.
Still no joy.
Digging deeper, I found the following issues.
Issue #1: Overly automatic implementation in rbSetValue_forKey
rbSetValue_forKey is automatically wrapping any access method
with willChangeValueForKey and didChangeValueForKey.
This should really be left to the accessor method, or in ruby
idiom, there should be
a meta-programming method to declare this sort of default accessor,
not mandatory.
Work around: Redefine rbSetValue_forKey in your subclass.
Issue #2: KVC/CoreData doesn't know about ruby accessors.
Fixing the above won't help, because NSManagedObject/CoreData ends
up never going into ruby at all, because the accessors are only
called via "valueForUndefinedKey" or "setValue:forUndefinedKey:".
With NSManagedObject, accessors are completely _optional_. If it
can't find an accessor, it uses primitiveValueForKey instead.
Workaround:
I commented out the code at cocoa_macros.rb:102 that seemed to
be blowing away MY accessors, and overrode the ruby version of
NSManagedObject to look in ruby first before relying on the
NSManagedObject implementation:
# find accesor for key-value coding
# "key" must be a ruby string
def kvc_getter_method(key)
[key, key + '?'].each do |m|
return m if respond_to? m
end
return nil # accessor not found
end
def kvc_setter_method(key)
[kvc_internal_setter(key), key + '='].each do |m|
return m if respond_to? m
end
return nil
end
def kvc_accessor_notfound(key)
fmt = '%s: this class is not key value coding-compliant for the
key "%s"'
raise sprintf(fmt, self.class, key.to_s)
end
def rbSetValue_forKey(value, key)
if m = kvc_setter_method(key.to_s)
send(m, value)
else
kvc_accessor_notfound(key)
end
end
def valueForKey(key)
print "aruby: valueForKey\n"
if m = kvc_getter_method(key.to_s)
return send(m)
else
super
end
end
def setValue_forKey(value,key)
print "aruby: setValue_forKey\n"
if m = kvc_setter_method(key.to_s)
send(m,value)
else
super
end
end
Long term:
I think that the ruby accessors need to be registered on the
objective-C side, because one of the strengths of KVC is that it only
is suppose to have to map key->accessor once. After that, it stores
an association.
Not sure how to do that though.
Pierce