Re: Declaring Java classes and methods

["colin williams" <colin.williams@xxxxxxxxxxxx>]

Joe,

if you need to write a custom classloader, there are some articles on the
IBM developerworks site that discuss this(assuming you havent done this
before!).

I recently knocked up a custom classloader so that i could setup my
classpath dynamically, rather than setting using the RUNJVA command.

I had an application that used a component dependent on a lot of open source
JARS, and I didnt want to type them all in to the classpath one by one.
So I created custom classloader that I could point at a directory, and it
would add all the jars to the classpath.

cheers
Colin.W

----- Original Message ----- 
From: <furgalj@xxxxxxxxxxxxxxxx>
To: <java400-l@xxxxxxxxxxxx>
Cc: <java400-l@xxxxxxxxxxxx>; <java400-l-bounces@xxxxxxxxxxxx>
Sent: Monday, August 30, 2004 3:36 PM
Subject: Re: Declaring Java classes and methods


> Joe Pluta wrote:
>
> >I'm a little unclear as to how tightly typed the type O variables are.
> >If I declare a type O variable as class Widget, must I instatiate an
> >object of type Widget to stick in there?  Can I use a subclass of
> >Widget?  Can I use a class that's NOT a subclass, provided the method I
> >later invoke has the same signature?
> >
> >I can do this with a factory method.  I'd have to instatiate the
> >factory, and then pass the class name into the factory as a parameter to
> >instantiate the actual object (or have a delegate method in the factory
> >that emulates the desired method, only taking a class name as well).  It
> >would be a little easier if I could do it in the RPG, is all.
>
> Joe, maybe I'm stating the obvious here, and you've already looked into
> this, but if not, it might be worth a try. I believe what you need is a
> custom class loader. You can write them yourself if you study how Java
> does it. This could be a static class and loader method, so that when you
> called it with the class.method variable name it would not have to be
> instantiated each time. You might even be able to do some of this in RPG,
> but I'm not at all sure about that. But I have seen and heard of people
> writing stranger class loaders than that -)! Also, as to your last point,
> can't you define interfaces for the classes and methods you're interested
> in ant invoke them via the interface method? By doing this you should be
> able to slip in almost anything as long as the signature matches.
>
>
> _________________________________________________________________
> Jeff Furgal / MIMIX User Interface Product Architect / Lakeview Technology
>
> furgalj@xxxxxxxxxxxxxxxx / 630-282-8360
>
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