You are viewing a plain text version of this content. The canonical link for it is here.
Posted to taglibs-user@tomcat.apache.org by Borislav Iordanov <bo...@speakeasy.net> on 2002/04/15 07:25:59 UTC

[JSTL] Java enum constants

Hi,

It would be useful if the JSTL expression language supported enum 
constants access through the '.' operator. For example:

class A
{
   public final static int  ENUM_1 = 0;
   public final static int ENUM_2 = 1;

  public int getType() // returns one of ENUM_1, ENUM_2 etc...
}


and then

<c:choose>
   <c:when test="${a.type == a.ENUM_1}">
    do something
  </c:when>
   <c:when test="${a.type == a.ENUM_2}">
    do something else
  </c:when>
</c:choose>

Could it be done?
Thanks,
Boris
   


--
To unsubscribe, e-mail:   <ma...@jakarta.apache.org>
For additional commands, e-mail: <ma...@jakarta.apache.org>

Re: [JSTL] Java enum constants

Posted by Borislav Iordanov <bo...@speakeasy.net>.
Hi,

I think accessing the static values of the class of the actual object 
would be fine (well-defined, clear, intuitive). But I agree it departs 
from the "objects with properties" model.

In any case, a mechanism for defining (and/or accessing) named constants 
would be nice.

Thanks for the quick response!

Regards,
Boris

Shawn Bayern wrote:

>Yeah, the topic has come up. It could be done in principle, but
>
> - it won't make it into JSTL 1.0
>
> - there are problems with referring to static members of a class
>   The JSTL EL just refers to objects, so it's not clear which class in
>   the object's ancestry hierarchy the static values would come from.  
>   We'd probably need to add a mechanism to refer to a class specifically,
>   and this would complicate a language that's intended to hide the
>   details of Java data types for page authors.
>
>Hope that helps,
>



--
To unsubscribe, e-mail:   <ma...@jakarta.apache.org>
For additional commands, e-mail: <ma...@jakarta.apache.org>

Re: [JSTL] Java enum constants

Posted by Shawn Bayern <ba...@essentially.net>.
Yeah, the topic has come up. It could be done in principle, but

 - it won't make it into JSTL 1.0

 - there are problems with referring to static members of a class
   The JSTL EL just refers to objects, so it's not clear which class in
   the object's ancestry hierarchy the static values would come from.  
   We'd probably need to add a mechanism to refer to a class specifically,
   and this would complicate a language that's intended to hide the
   details of Java data types for page authors.

Hope that helps,

-- 
Shawn Bayern
Author, "JSP Standard Tag Library"  http://www.jstlbook.com
(coming this summer from Manning Publications)

On Mon, 15 Apr 2002, Borislav Iordanov wrote:

> Hi,
> 
> It would be useful if the JSTL expression language supported enum 
> constants access through the '.' operator. For example:
> 
> class A
> {
>    public final static int  ENUM_1 = 0;
>    public final static int ENUM_2 = 1;
> 
>   public int getType() // returns one of ENUM_1, ENUM_2 etc...
> }
> 
> 
> and then
> 
> <c:choose>
>    <c:when test="${a.type == a.ENUM_1}">
>     do something
>   </c:when>
>    <c:when test="${a.type == a.ENUM_2}">
>     do something else
>   </c:when>
> </c:choose>
> 
> Could it be done?
> Thanks,
> Boris
>    
> 
> 
> --
> To unsubscribe, e-mail:   <ma...@jakarta.apache.org>
> For additional commands, e-mail: <ma...@jakarta.apache.org>
> 


--
To unsubscribe, e-mail:   <ma...@jakarta.apache.org>
For additional commands, e-mail: <ma...@jakarta.apache.org>