Groups > comp.lang.java.programmer > #17080

Re: Type of a generic class?

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From	"markspace" <markspace@1:261/38.remove-yy0-this>
Subject	Re: Type of a generic class?
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  To: Donkey Hottie
From: markspace <-@.>

On 8/2/2012 4:27 PM, Donkey Hottie wrote:

> It is indeed kind of spooky and strange idea, after all what is so wrong
> about simple
>
>      String value = SystemProperties.getString("ParamName") ;
>
> It is OK, but I'm kind of toying with idea of strong typing of System
> Parameters: A Date can not be stored as Long or Double etc..

To do something like this, I'd arrange some implementation for the parameter:

class Parameter {
   public void processParam( String param ) {
      double d = Double.parse( param ); // or whatever...
      ...
   }
}

And then use a Map as Lew suggests or some other method of binding the 
Parameter class to the string "ParamName".

(You could, for example use Class.forName():
   Parameter proc = Class.forName(
"my.project.parameter."+"ParamName").newInstance();

or you could use annotations:

@Parameter("ParamName")
class Parameter {...

or any other crazy thing you like.  It would probably be better than what you 
have now.)

> The back end of the system parameters is simply
>
> CREATE TABLE SystemParameters
> (
>      name varchar(64) not null primary_key,
>      value varchar(512)
> ) ;

I've written this table definition.  In fact it was 23 odd years ago, as in 
intern while still in college.  I don't know if it's good or bad practice, but 
it seems a common idea.

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Thread

Type of a generic class? "Donkey Hottie" <donkey.hottie@1:261/38.remove-yy0-this> - 2012-08-03 18:54 +0000
  Re: Type of a generic class? "Lew" <lew@1:261/38.remove-yy0-this> - 2012-08-03 18:54 +0000
  Re: Type of a generic class? "markspace" <markspace@1:261/38.remove-yy0-this> - 2012-08-03 18:54 +0000
    Re: Type of a generic class? "Donkey Hottie" <donkey.hottie@1:261/38.remove-yy0-this> - 2012-08-03 18:54 +0000
      Re: Type of a generic class? "Lew" <lew@1:261/38.remove-yy0-this> - 2012-08-03 18:54 +0000
      Re: Type of a generic class? "markspace" <markspace@1:261/38.remove-yy0-this> - 2012-08-03 18:54 +0000
        Re: Type of a generic class? "Donkey Hottie" <donkey.hottie@1:261/38.remove-yy0-this> - 2012-08-03 18:54 +0000
  Re: Type of a generic class? "Donkey Hottie" <donkey.hottie@1:261/38.remove-5qr-this> - 2012-08-04 18:41 +0000

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