[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.