Re: How to pass a Java callable to C#?

>From the Java side, the on_click method signature is:

on_click(Lcli/System/Func$$00602_$$$_Ljava__lang__Object_$$_Ljava__lang__Object_$$$$_)V

The ugliness of the name is due to generics, but not really relevant to this discussion.

If you reflect on this class, you can determine it is a .NET delegate (it extends cli.System.MulticastDelegate and has a nested class called Method with a single Invoke method and it (the delegate class) has a constructor taking a reference to the inner Method interface).

BTW, I just realized you can also use one of the static methods on Delegate to create a delegate to the specified method and simply pass that.

Regards,
Jeroen

> -----Original Message-----
> From: Doug Blank [mailto:[email protected]]
> Sent: Monday, February 17, 2014 16:25
> To: Jeroen Frijters
> Cc: [email protected]
> Subject: Re: [Ikvm-developers] How to pass a Java callable to C#?
> 
> On Sun, Feb 16, 2014 at 8:41 AM, Jeroen Frijters <[email protected]
> <mailto:[email protected]> > wrote:
> 
> 
> 	Hi Doug,
> 
> 	Your C# on_click method is callable from (IKVM) Java.
> 
> 	You'll need to generate a class that implements the
> cli.System.Func$$00602_$$$_Ljava__lang__Object_$$_Ljava__lang__Object_$$
> $$_$Method interface.
> 
> 
> 
> 
> Jeroen,
> 
> Thanks for these details; can you expand a bit on this?
> Where did the name
> "cli.System.Func$$00602_$$$_Ljava__lang__Object_$$_Ljava__lang__Object_$
> $$$_$Method" come from?
> What is that?
> How do you create an interface that implements it?
> 
> I've read and googled looking for details on signatures and IKVM, but I
> can't find anything that appears to be relevant.
> 
> -Doug
> 
> 
> 	This class can then be instantiated and passed to the constructor
> of the
> cli.System.Func$$00602_$$$_Ljava__lang__Object_$$_Ljava__lang__Object_$$
> $$_ class (the delegate) and this object can be passed to the on_click
> method.
> 
> 
> 	Regards,
> 	Jeroen
> 
> 	> -----Original Message-----
> 	> From: Doug Blank [mailto:[email protected]
> <mailto:[email protected]> ]
> 
> 	> Sent: Sunday, February 16, 2014 13:46
> 	> To: Jeroen Frijters
> 	> Cc: [email protected] <mailto:ikvm-
> [email protected]>
> 	> Subject: Re: [Ikvm-developers] How to pass a Java callable to C#?
> 	>
> 	> Jeroen,
> 	>
> 	> Thanks for the feedback, but I think I didn't explain very well
> my
> 	> problem. The Widget library is written in C# and is being used by
> the
> 	> Java interpreter (running on the CLR). I wish to be able to
> register the
> 	> callback in Java.
> 	>
> 	> This works in IronPython, because IronPython knows how to map
> Python
> 	> functions onto Func<object,object>:
> 	>
> 	> """
> 	> from Widgets import Widget
> 	> def f(obj):
> 	>     print("Click!")
> 	> w = Widget()
> 	> w.on_click(f)
> 	> """
> 	>
> 	> I have the same working in a Scheme running on the CLR, because I
> can
> 	> define and wrap around callback1 in C#  to map it to
> 	> Func<object,object>:
> 	>
> 	> """
> 	> (using "Widgets")
> 	> (define f (lambda (obj) (printf "~a\n" obj)) (define w (Widget))
> 	> (w.on_click (callback1 f)) """
> 	>
> 	> So, I'm trying to figure out how to do the same thing in Java:
> map
> 	> something in Java onto Func<object,object>, so something like
> this will
> 	> work in DynamicJava:
> 	>
> 	> """
> 	> import static cli.Widgets.*;
> 	>
> 	> public int f(Object widget) {
> 	> }
> 	>
> 	> Widget w = new Widget();
> 	> w.on_click(f);
> 	> """
> 	>
> 	> Does ikvm have something built-in to help pass a Java function to
> C#? Or
> 	> do you have a general strategy for doing this?
> 	>
> 	> Thanks for any further hints,
> 	>
> 	> -Doug
> 	>
> 	>
> 	> On Sun, Feb 16, 2014 at 4:21 AM, Jeroen Frijters
> <[email protected] <mailto:[email protected]>
> 
> 	> <mailto:[email protected] <mailto:[email protected]> > > wrote:
> 	>
> 	>
> 	>       Hi Doug,
> 	>
> 	>       I'm probably misunderstanding the question, but in Java
> you'd use
> 	> interfaces for this. See
> 	>
> http://docs.oracle.com/javase/7/docs/api/java/awt/Button.html#addActionL
> 	> istener(java.awt.event.ActionListener) for example.
> 	>
> 	>       Regards,
> 	>       Jeroen
> 	>
> 	>
> 	>       > -----Original Message-----
> 	>       > From: Doug Blank [mailto:[email protected]
> <mailto:[email protected]>
> 	> <mailto:[email protected] <mailto:[email protected]> > ]
> 	>       > Sent: Sunday, February 16, 2014 0:57
> 
> 	>       > To: [email protected] <mailto:ikvm-
> [email protected]>  <mailto:ikvm- <mailto:ikvm->
> 	> [email protected]
> <mailto:[email protected]> >
> 	>       > Subject: [Ikvm-developers] How to pass a Java callable to
> C#?
> 	>       >
> 	>       > I am doing some refining on the DynamicJava interpreter
> written
> 	> in Java
> 	>       > that is running under Mono [1]. (C# libraries are made
> available
> 	> to the
> 	>       > interpreted Java through ikvmstub, and the Java
> interpreter is
> 	> running
> 	>       > by being compiled with ikvmc). Everything is working very
> well,
> 	> but one
> 	>       > thing I would like to do is be able to pass a Java
> callback to a
> 	> C#
> 	>       > function.
> 	>       >
> 	>       >
> 	>       > The C# code looks like this (although I could change it
> in any
> 	> manner):
> 	>       >
> 	>       >
> 	>       > public class Widget {
> 	>       > public void on_click(System.Func<object,object> function)
> {
> 	>       >         }
> 	>       > }
> 	>       >
> 	>       > In general, how would a Java program register a callback
> to the
> 	> C#? I
> 	>       > can write an interface on either the Java side, or the C#
> side.
> 	>       >
> 	>       > Thanks for any suggestions,
> 	>       >
> 	>       > -Doug
> 	>       >
> 	>       > [1] -
> 	>       >
> 	>
> https://bitbucket.org/ipre/calico/src/master/languages/Java/dynamicjava/
> 	>
> 	>
> 
> 
> 


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