springframework-developer

[Springframework-developer] property editor doesn't know existing property value when setting new value using BeanWrapperImpl

[Tom T. <tom...@pr...>]

When using BeanWrapperImpl to set the value of a property where a
property editor is involved, doTypeConversionIfNecessary() calls
setAsText() and then getValue() on the property editor, but it does not
first call setValue() with the existing property value. Hence, you
cannot use getValue() in the setAsText() method to get the existing
property value...

I accidentally discovered this when trying to get
MutableSortDefinition's toggleAscendingOnProperty functionality to work
when binding a sortDefinition request parameter on a bean that is kept
in the session. It doesn't work, because my property editor's
setAsText() method never updates the existing MutableSortDefinition
property value - getValue() is always null and a new instance is created
every time.

Actually, I would really expect this to work... I have a lot of custom
property editors where setAsText() performs a database lookup by primary
key, but first performs a !getAsText().equals(text) check to verify the
lookup is actually necessary. Probably, this doesn't work either,
because getAsText() calls getValue() to transform the existing property
value into a String representation...

In fact, when looking at BeanWrapperImpl's source, it turns out the
oldValue parameter passed to doTypeConversionIfNecessary is explicitly
specified as null everywhere the method is called, but the parameter is
only used for creating property change events anyway.

I searched the forums and noticed there's already a "discussion" going
on ;-)

http://forum.springframework.org/viewtopic.php?t=3440

I couldn't find a JIRA issue for this yet, so I've created one:

http://opensource.atlassian.com/projects/spring/browse/SPR-1155

Any chance this can be fixed?

Thanks,
Tom.

Re: [Springframework-developer] property editor doesn't know existing property value when setting new value using BeanWrapperImpl

[Juergen H. <ju...@in...>]

That's actually a good idea... I wouldn't call it a fix, rather an
enhancement: Old values simply weren't exposed to PropertyEditors before.

I've just reworked BeanWrapperImpl accordingly. After some fine tuning,
everything seems to run nicely. I'm gonna release this in 1.2.3. If there's
any further refinements in that area that you'd like to see, let me know :-)

Juergen


-----Original Message-----
From: spr...@li...
[mailto:spr...@li...] On Behalf Of
Tom Turelinckx
Sent: Wednesday, July 20, 2005 10:32 AM
To: spr...@li...
Subject: [Springframework-developer] property editor doesn't know existing
property value when setting new value using BeanWrapperImpl

When using BeanWrapperImpl to set the value of a property where a property
editor is involved, doTypeConversionIfNecessary() calls
setAsText() and then getValue() on the property editor, but it does not
first call setValue() with the existing property value. Hence, you cannot
use getValue() in the setAsText() method to get the existing property
value...

I accidentally discovered this when trying to get MutableSortDefinition's
toggleAscendingOnProperty functionality to work when binding a
sortDefinition request parameter on a bean that is kept in the session. It
doesn't work, because my property editor's
setAsText() method never updates the existing MutableSortDefinition property
value - getValue() is always null and a new instance is created every time.

Actually, I would really expect this to work... I have a lot of custom
property editors where setAsText() performs a database lookup by primary
key, but first performs a !getAsText().equals(text) check to verify the
lookup is actually necessary. Probably, this doesn't work either, because
getAsText() calls getValue() to transform the existing property value into a
String representation...

In fact, when looking at BeanWrapperImpl's source, it turns out the oldValue
parameter passed to doTypeConversionIfNecessary is explicitly specified as
null everywhere the method is called, but the parameter is only used for
creating property change events anyway.

I searched the forums and noticed there's already a "discussion" going on
;-)

http://forum.springframework.org/viewtopic.php?t=3440

I couldn't find a JIRA issue for this yet, so I've created one:

http://opensource.atlassian.com/projects/spring/browse/SPR-1155

Any chance this can be fixed?

Thanks,
Tom.


-------------------------------------------------------
SF.Net email is sponsored by: Discover Easy Linux Migration Strategies from
IBM. Find simple to follow Roadmaps, straightforward articles, informative
Webcasts and more! Get everything you need to get up to speed, fast.
http://ads.osdn.com/?ad_id=7477&alloc_id=16492&op=click
_______________________________________________
Springframework-developer mailing list
Spr...@li...
https://lists.sourceforge.net/lists/listinfo/springframework-developer