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Re: methodhandles lookup

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On Fri, 22 Jan 2016 03:13:31 -0800, Philipp Kraus wrote:

> Okay thanks.
> 
> In my system I have got a component which creates the MethodHandle
> objects from the Method object, so can I create based on the Method
> object the handle object on its signature?

If you can obtain the correct Class<?> from Method you might use one of 
the MethodType.methodType(Class<?>, ...) methods. Not sure how fuzzy this 
might get when considering such things as bridge or synthetic methods.

> Can you explain how? In my case I will cache all Method objects and
> build the handlers during runtime, is this fast enough?

Fast enough for what?
Not fair answering a question with a question?
Ok then, try it.

> 
> Thanks
> 
> Phil
> 
> 
> Am Freitag, 22. Januar 2016 12:04:37 UTC+1 schrieb Jeff Higgins:
>> On Fri, 22 Jan 2016 00:19:07 -0800, Philipp Kraus wrote:
>> 
>> > Hello,
>> > 
>> > I'm trying to create a flexible (dynamic) binding for method calls
>> > and I have got a problem with overloaded method binding.
>> > In detail: I have created an own programming language which should
>> > call a java method. In my own language I have got grammar constructs
>> > like "foo/bar( "myobject" );". Internal I have got a Map<String,
>> > Object> which maps the string parameter to an object which will be
>> > invoked. foo/bar points to the method, in this case foo is the
>> > classname and bar the method name. So in this example I need a
>> > binding to the method "public void bar();".
>> > My language should also use calls like "foo/bar( "myobject", 1 );".
>> > In this case the Java method "void bar( int x );" should be called.
>> > 
>> > The basic invoking call works well, but I overloaded method creates a
>> > problem. If I have got the class
>> > 
>> > class foo {
>> >      public void bar()
>> >      {
>> >           System.out.println("test");
>> >      }
>> > }
>> > 
>> > I do the following:
>> > 
>> > final Multimap<String, MethodHandle> y = HashMultimap.create();
>> > for ( final Method x : foo.class.getDeclaredMethods() )
>> >     y.put( x.getSimpleName(), MethodHandles.lookup().unreflect(x) );
>> > 
>> > This multimap is put to the parser / lexer of my language to resolve
>> > method names but on calling / invoking I get the problem, that I need
>> > the correct methodhandle within the multimap depend on the signature.
>> > 
>> > The problem is a class like class foo {
>> >      public void bar()
>> >      {
>> >           System.out.println("test");
>> >      }
>> > 
>> >      public void bar( int x )
>> >      {
>> >           System.out.println("test " + x);
>> >      }
>> > }
>> > 
>> > So my question is, how can I create a dynamic binding on method
>> > handles depend on the signature?
>> 
>> For each MethodHandle examine its MethodType and proceed from there.
>> 
>> > And can I cache the method handles / is it a good choice of caching
>> > all handles? In my case I know during runtime the concrete signature
>> > of the method, "foo/bar" is executed and on this time I know all
>> > arguments of the method, so I can create at this point the binding.
>> > How can I do this in a fast way?
>> > 
>> > Thanks
>> > 
>> > Phil

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Thread

methodhandles lookup Philipp Kraus <philipp.kraus.flashpixx@gmail.com> - 2016-01-22 00:19 -0800
  Re: methodhandles lookup Jeff Higgins <jeff@invalid.invalid> - 2016-01-22 08:57 +0000
  Re: methodhandles lookup Jeff Higgins <jeff@invalid.invalid> - 2016-01-22 11:01 +0000
    Re: methodhandles lookup Philipp Kraus <philipp.kraus.flashpixx@gmail.com> - 2016-01-22 03:13 -0800
      Re: methodhandles lookup Jeff Higgins <jeff@invalid.invalid> - 2016-01-22 11:43 +0000
        Re: methodhandles lookup Jeff Higgins <jeff@invalid.invalid> - 2016-01-22 12:03 +0000
          Re: methodhandles lookup Philipp Kraus <philipp.kraus.flashpixx@gmail.com> - 2016-01-24 01:59 -0800
      Re: methodhandles lookup Jeff Higgins <jeff@invalid.invalid> - 2016-01-22 12:16 +0000
        Re: methodhandles lookup Jan Burse <janburse@fastmail.fm> - 2016-01-22 17:12 +0100
  Re: methodhandles lookup Martin Gregorie <martin@address-in-sig.invalid> - 2016-01-22 11:27 +0000
    Re: methodhandles lookup Philipp Kraus <philipp.kraus.flashpixx@gmail.com> - 2016-01-24 01:56 -0800
  Re: methodhandles lookup Jan Burse <janburse@fastmail.fm> - 2016-01-22 16:49 +0100

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