So this is what I now have:
namespace ObjectFactory {
[CCode (has_target = false)]
public delegate Object Maker();
Gee.HashMap<Type,Maker> construct_map;
public void add_maker(Type for_type, Maker maker) {
if (construct_map == null) {
construct_map = new Gee.HashMap<Type,Maker>();
}
construct_map[for_type] = maker;
}
public Object? make(Type one_of_these) {
if (construct_map != null && construct_map.has_key (one_of_these)) {
Maker m = construct_map[one_of_these];
return m ();
}
return null;
}
}
and then in each instantiation:
public class IntArr : GArrSerializable<int> {
class construct {
ObjectFactory.add_maker(typeof (IntArr), () => { return new IntArr ();
});
}
public IntArr(int size = 0) {
base (size);
}
}
then I use ObjectFactory.make (type) in my deserialization procedure, and
it appears to work ok at last.
On Wed, Feb 17, 2016 at 10:26 AM, Andy Lees <andrewl...@gmail.com> wrote:
> Momentarily I thought that might work, but it does match the Json
> serialization structure - the context of deserializing an array does not
> provide the initialised array, the deserialization procedure has to do the
> creation, and only has the type id to work with. It looks like I'll have
> to create an object factory of my own for this, as I don't want to get into
> the internals of Json glib.
>
> On Wed, Feb 17, 2016 at 10:09 AM, Daniel Espinosa <eso...@gmail.com>
> wrote:
>
>> I run in the same issue for GXml and SerializableListArray<>, for example.
>>
>> The way I resolve, in my case, I've defined a new Interface called
>> SerializableCollection, with a init() function. This function is called by
>> Serializable.deserialize() method in order to help implementators to
>> initialize its generic containers by calling MyObjectCollection.new()
>> providing any information it needs like the Generic Type it should work on.
>>
>> In my other project, I've just initialize any public property as
>>
>> MyProperty<int> prop { get; set; default = new MyProperty<int>(); }
>>
>> or inside construct {}
>>
>> The point is to call MyProperty.new() not Object.new() on generic classes.
>>
>>
>> 2016-02-16 16:59 GMT-06:00 Andy Lees <andrewl...@gmail.com>:
>>
>>> Yes, the problem is that for types derived from generics (and for the
>>> generic constructor itself), the type information is not set in the
>>> construct function, so very little can be done.
>>>
>>> On Wed, Feb 17, 2016 at 9:53 AM, Daniel Espinosa <eso...@gmail.com>
>>> wrote:
>>>
>>>> If you want to execute code on Object creation using Object.new(), you
>>>> should use
>>>>
>>>> construct {
>>>> // Your code here
>>>> }
>>>>
>>>> When define code at MyObject.new(), you execute the code in this method
>>>> not Object.new(), then use the above should help.
>>>>
>>>>
>>>> 2016-02-16 15:58 GMT-06:00 Andy Lees <andrewl...@gmail.com>:
>>>>
>>>>> The problem with Object.new is that it doesn't call the object
>>>>> constructor so far as I can tell, just calling g_object_new without any of
>>>>> the Vala object construction code.
>>>>>
>>>>> My Serializable is an interface. I'm trying to make use of the Json
>>>>> serialization framework, and for the most part it's working. The problem
>>>>> I'm having is with the construction of instances of array types - there
>>>>> appears to be no factory framework for object creation in Vala, and so far
>>>>> the only workaround I've come up with is very clunky.
>>>>>
>>>>> Is there an object factory somewhere that someone could point me
>>>>> towards?
>>>>>
>>>>> On Wed, Feb 17, 2016 at 1:49 AM, Daniel Espinosa <eso...@gmail.com>
>>>>> wrote:
>>>>>
>>>>>> Try use Object.new(typeof(IntArr))
>>>>>>
>>>>>> Try to rename type() to any other, to avoid conflics with
>>>>>> Object.type()
>>>>>>
>>>>>> You are trying to implement Gee.ArrayList<>, may you:
>>>>>>
>>>>>> A) wrap Gee.ArrayList in your class
>>>>>>
>>>>>> B) Derive directly from Gee.Arraylist then convert your base class
>>>>>> Serializable as an interface with all required methods implemented as
>>>>>> virtual, then you have two bases.
>>>>>>
>>>>>> You may want to check at GXml.Serializable interface and its
>>>>>> GXml.SerializableArrayList implementation based on Gee.
>>>>>> El feb. 16, 2016 7:10 AM, "Andy Lees" <andrewl...@gmail.com>
>>>>>> escribió:
>>>>>>
>>>>>>> I would have expected the generic type to be obtained from the type
>>>>>>> id of the derived type (generic instantiation), which is obtained fresh
>>>>>>> each execution, but it seems not. Is the generic type a hidden
>>>>>>> property of
>>>>>>> the class derived from the generic class, and if so, what would its
>>>>>>> name be
>>>>>>> so that it can be set in the new call?
>>>>>>>
>>>>>>> Alternatively, is there a way to call an object constructor given
>>>>>>> the type id?
>>>>>>>
>>>>>>> On Tue, Feb 16, 2016 at 11:16 PM, Daniel Espinosa <eso...@gmail.com>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> Take in account that Type system is dynamically created, then a
>>>>>>>> type number will change with each execution.
>>>>>>>>
>>>>>>>> Use
>>>>>>>>
>>>>>>>> YourCreatedObject is typeof (Object)
>>>>>>>>
>>>>>>>> to check if the created object is of type you need, like a derived
>>>>>>>> object.
>>>>>>>>
>>>>>>>> You can use
>>>>>>>>
>>>>>>>> obj.get_type().is_a(typeof (Object))
>>>>>>>>
>>>>>>>> And consider that your example is exactly the way to create an
>>>>>>>> object of Generic class, because you have set tje object type. Create a
>>>>>>>> generic instance with Object.new you should provide the object type.
>>>>>>>> El feb. 16, 2016 5:14 AM, "Andy Lees" <andrewl...@gmail.com>
>>>>>>>> escribió:
>>>>>>>>
>>>>>>>>> Hi,
>>>>>>>>>
>>>>>>>>> I have a generic array implementation like so:
>>>>>>>>>
>>>>>>>>> public class GArrSerializable<T> : Serializable, Object {
>>>>>>>>> public T[] data;
>>>>>>>>> public int length;
>>>>>>>>> public GArrSerializable(int size = 0) {
>>>>>>>>> data = new T[size];
>>>>>>>>> }
>>>>>>>>>
>>>>>>>>> public Type type () { return typeof (T); }
>>>>>>>>>
>>>>>>>>> ...etc
>>>>>>>>>
>>>>>>>>> and a derived type:
>>>>>>>>>
>>>>>>>>> public class IntArr : GArrSerializable<int> {
>>>>>>>>>
>>>>>>>>> public IntArr(int size = 0) {
>>>>>>>>> base (size);
>>>>>>>>> }
>>>>>>>>> }
>>>>>>>>>
>>>>>>>>> If I create an instance of the type, then instance.type () returns
>>>>>>>>> 24 as
>>>>>>>>> expected.
>>>>>>>>> If I create an instance like so:
>>>>>>>>> var ia = Object.@new (type) as IntArr;
>>>>>>>>> var t = ia.type ();
>>>>>>>>>
>>>>>>>>> Then t is 4 rather than 24. As it is in the instance when it
>>>>>>>>> tries to
>>>>>>>>> deserialize.
>>>>>>>>>
>>>>>>>>> Can you tell me why this is so, and how I can programmatically
>>>>>>>>> create
>>>>>>>>> objects derived from a parameterised type?
>>>>>>>>>
>>>>>>>>> Thanks
>>>>>>>>>
>>>>>>>>> Andrew Lees
>>>>>>>>> _______________________________________________
>>>>>>>>> vala-list mailing list
>>>>>>>>> vala-list@gnome.org
>>>>>>>>> https://mail.gnome.org/mailman/listinfo/vala-list
>>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> Trabajar, la mejor arma para tu superación
>>>> "de grano en grano, se hace la arena" (R) (en trámite, pero para los
>>>> cuates: LIBRE)
>>>>
>>>
>>>
>>
>>
>> --
>> Trabajar, la mejor arma para tu superación
>> "de grano en grano, se hace la arena" (R) (en trámite, pero para los
>> cuates: LIBRE)
>>
>
>
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