Re: Discussion: The Form Widget use-when attribute

[Adrian Crum]

The BeanShell operator overload works after all. I don't know why I was 
having a problem with it earlier.

Now that it appears to be working correctly, I have decided against 
making this change.

-Adrian

Scott Gray wrote:
The more I think about it the less I like void values anyway, it just 
increases the likely hood of unintended behavior.  I say we go for it 
and let the exceptions be thrown and then fix them by actually 
initializing the values.

Regards
Scott

On 5/05/2009, at 5:53 PM, Adrian Crum wrote:


The UEL throws an exception if an undefined value is used in an 
expression. I added an extension that allows you to specify a default 
value if one isn't found. So, it would look like this: 
${partyIdfrom$string == ''}.

I tried to use the operator overload in BeanShell, but it threw a 
parse exception. I don't know what that is about.

-Adrian


--- On Mon, 5/4/09, Scott Gray <scott.g...@hotwaxmedia.com> wrote:

From: Scott Gray <scott.g...@hotwaxmedia.com>
Subject: Re: Discussion: The Form Widget use-when attribute
To: dev@ofbiz.apache.org
Date: Monday, May 4, 2009, 9:51 PM
I don't mind either way, only one question, how does UEL
handle undefined values e.g. (partyIdFrom == void) would we
just do (partyIdFrom == null)?

It's also worth mentioning that we never needed to use
XML escaping for beanshell it was the one that supported the
method I suggested for UEL.

Regards
Scott

On 5/05/2009, at 4:33 PM, Adrian Crum wrote:


Now that the UEL supports logical operator
substitution
(http://docs.ofbiz.org/display/OFBTECH/Unified+Expression+Language+(JSR-245)+in+OFBiz#UnifiedExpressionLanguage%28JSR-245%29inOFBiz-OperatorSubstitutions) 

we have the ability to eliminate the clumsy XML escaping in
the form widget use-when attribute. The problem is, the form
widget evaluates the use-when attribute with BeanShell, not
UEL.

I would like to change the form widget to use UEL in
use-when expression evaluations. The use-when attribute must
evaluate to a boolean, and UEL is perfect for that. Plus,
expression evaluation using UEL should execute faster than
BeanShell.

The potential downside is the chance there is a
peculiar use-when expression that BeanShell can evaluate,
but UEL can't. Those should be easy to find though.

What do you think?

-Adrian