Re: [xmlvm-users] Implementing new class in Objective-C

[Arno P. <ar...@pu...>]

the preferred way is to do as much as possible in Java and then 
cross-compile to Objective-C. If you already have an Objective-C class 
that you want to expose in Java, you need to create a Java stub and then 
write some "glue" code in Objective-C that bridges the Java API to the 
Objective-C API. This is necessary because of the certain differences 
between the languages. E.g., we have to use name mangling when 
cross-compiling from Java to Objective-C and the "glue" code needs to do 
a mapping from the mangled version of a name to the original version. 
Here is an example taken from 
xmlvm/src/xmlvm2objc/compat-lib/objc/org_xmlvm_iphone_UIImage.m:

+ (org_xmlvm_iphone_UIImage*) imageWithContentsOfFile___java_lang_String 
:(java_lang_String*)path
{
     return [[UIImage alloc] initWithContentsOfFile:path];
}

The new C backend (once its done), can automate some of the boilerplate 
code that currently needs to be done manually in Objective-C. Here is 
the same example from the C backend:

JAVA_OBJECT 
org_xmlvm_iphone_UIImage_imageWithContentsOfFile___java_lang_String(JAVA_OBJECT 
n1)
{
     if (!__CLASS_org_xmlvm_iphone_UIImage.classInitialized)
         __INIT_org_xmlvm_iphone_UIImage();
 
//XMLVM_BEGIN_WRAPPER[org_xmlvm_iphone_UIImage_imageWithContentsOfFile___java_lang_String]
	
     NSString *nsStr = toNSString(n1);
     UIImage *named = [UIImage imageNamed:nsStr];
	
     org_xmlvm_iphone_UIImage *toRet = __NEW_org_xmlvm_iphone_UIImage();
     toRet->org_xmlvm_iphone_UIImage.ocImage = named;
     return toRet;
     //XMLVM_END_WRAPPER
}

Only the code between the //XMLVM_* comments was written by hand; the 
rest was generated by the C backend.

Arno



On 11/30/10 1:48 AM, Tomas Vestelind wrote:
> Hi,
>
> I'm doing a proof-of-concept implementation with XMLVM for my master's
> thesis.
>
> I have a mobile application which uses a in-house framework and my goal
> is to make the program cross compile with XMLVM and do the framework
> components either in Objective-C or in Java then cross compiling it to
> Objective-C. So, I'm wondering how you do when you implement new classes
> in Objective-C. I will need this for our classes and possibly for Cocoa
> classes that are not implemented.
>
>  From what I have understood you create stubs in Java and then use XMLVM
> to generate Objective-C source files from these. Then you do the
> implementation of each class manually. Is this correct?
>
> If this is the case and I would like to implement a new class in
> Objective-C, would I do my skeleton in Java, generate the Objective-C
> code and do the implementation in Objective-C?
>
> Best regards,
> Tomas Vestelind
>
> ps. I think
> https://sites.google.com/a/xmlvm.org/documentation/home should be on
> www.xmlvm.org <http://www.xmlvm.org>
>
> --
> Quand on veut un mouton, c'est la preuve qu'on existe
>
>
>
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