Re: Class<T> question

On 2007.12.05., at 17:25, Gart, Mitchell wrote:

> Thanks, it worked to use Class<?> instead of just Class.
>
> In the example you cite, couldn't you have declared
>
>   Map<Object, String> map = new HashMap<Object, String>();
>
> Instead of
>
>   Map<? extends Object, String> map = new HashMap<Object, String>();

Actually, the first form would have been right -- I was typing from  
memory, sorry. I'm not really good with generics yet. I guess I should  
just refrain from giving generics-related advice for now.

Attila.

>
>
>
> - Mitch
>
>
> -----Original Message-----
> From: Discussion of advanced Java topics.
> [mailto:[email protected]] On Behalf Of Attila Szegedi
> Sent: Wednesday, December 05, 2007 10:49 AM
> To: [email protected]
> Subject: Re: [ADVANCED-JAVA] Class<T> question
>
> In my recent wrestling with "genericizing" a codebase that was
> originally pre-Java 5, I'd suggest you try replacing "Class" with
> "Class<?>".
>
> Alternatively, disable compiler warning for generics. No, seriously.
> Honestly, my feeling is that programming with generics causes more
> noise in source code than it eliminates. Yeah, it eliminates casts,
> but previously I would write:
>
> Map map = new HashMap();
> ...
> String x = (String)map.get(blah);
>
> Now I write monstrosities such as:
>
> Map<? extends Object, String> map = new HashMap<Object, String>();
> ...
> String x = map.get(blah);
>
> So, I need to write one cast less, and four type specifiers more. Net
> loss in code conciseness.
> I guess I'm just getting old and resistant to change.
>
> Attila.
>
> On 2007.12.05., at 14:12, Gart, Mitchell wrote:
>
>> I am trying to get rid of some compiler warnings in our code.  We
>> have a
>> method:
>>
>>  public static Logger getLogger(Class c) {
>>     return new Log4jLogger(c.getName());
>>  }
>>
>> and the compiler produces this warning:
>>
>>  Class is a raw type. References to generic type Class<T> should be
>> parameterized
>>
>> It is because Class is a generic type but I don't quite understand
>> how I
>> would change the declaration of the method, and the calls to the
>> method,
>> to make it parameterized and get rid of the warning.  Can somebody
>> explain this a little bit?  Thanks.
>>
>> - Mitch Gart
>
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Attila.

--
home: http://www.szegedi.org
weblog: http://constc.blogspot.com

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