Hi,
Am Samstag, den 19.01.2008, 22:31 +0100 schrieb Tobias Bocanegra:
> hi,
> the current ujax post servlet writes back all eligible input values to
> their respective properties. if the input values are empty strings,
> properties with empty strings are created. i think this behavior is
> not always desired. absent properties might mean something different
> than properties with empty strings (null vs. ""). i can imagine the
> opposite, too. where applications want all properties to be filled in.
>
> this problem is even more important when dealing with non-string
> properties. e.g. a number input which is not filled in, does not
> automatically mean '0'.
>
> there are several ways how to control this behavior:
> 1) do not include 'empty' values in the post.
> this requires some javascript preprocessing of the form which removes
> the empty inputs or mangles their names (i.e. removing the
> 'saveprefix').
>
> 2) ignore empty strings for non-existent, non-mandatory properties.
> this way, no superfluous properties are created. but the application
> must be aware of the fact that empty values might not create the
> properties. if a property is already set, sending an empty string
> would of course not remove the property but modify its value.
>
> 3) treat empty strings as 'null' value
> this means, that empty strings do not create empty properties and
> delete existing (non-mandatory) properties.
>
Basically I agree, but ...
> I think all the above could be handled with a default value hint:
> ./[EMAIL PROTECTED] = "" --> treat them as empty strings (1).
Do we need this special definition ? see below
> ./[EMAIL PROTECTED] = "ujax:ignore" --> ignore them (2)
+1
> ./[EMAIL PROTECTED] = "ujax:null" --> remove them (3)
+1
> ./[EMAIL PROTECTED] = "foobar" --> "normal" default value behavior
I would say, that in this case the "foobar" would be taken as the
DefaultValue (is this already the case today ??) This would alos handle
the first case of having an empty DefautlValue, thus leaving just three
cases:
ujax:ignore -> take "empty" string as "don't change current value
(if any)"
ujax:null - > take "empty" string as "remove property"
any thing else -> use provided value for property in case of empty
string
Regards
Felix
>
> where the first would remain the default behavior.
>
> WDYT ?
> regards, toby
>
