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https://issues.apache.org/jira/browse/WICKET-3269?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12975882#action_12975882
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Sven Meier commented on WICKET-3269:
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> it makes sense that empty strings are converted to nulls, this is what 99% of
> users expect.
I have to disagree on this generalized statement.
>what if the TextField holds an Integer? we cant push an empty string into the
>model then, but we can a >null. nulls are more universal then empty strings.
This is a straw man argument: This feature request has no intention to change
anything about handling type conversion and/or null conversion of non-String
types. It's about removing the special handling of the String type.
>providing an application-wide setting also will not work as it will break
>component libs that expect empty >strings to be converted to nulls.
Do you have an example case where this would be problematic?
>it is not a job of a converter to perform value->null conversions. converters
>are there for type conversion, not string manipulation.
Actually they do so already, see AbstractIntegerConverter subclasses as
examples.
>this can be toggled application-wide by using IComponentOnBeforeRenderListener
>to toggle the setting to false
This wouldn't allow to explicitly change the setting for a single component.
IMHO this is the wrong decision. Could we get opinions from other devs on this
issue?
Thanks
> Review AbstractTextComponent's handling of empty Strings in 1.5
> ---------------------------------------------------------------
>
> Key: WICKET-3269
> URL: https://issues.apache.org/jira/browse/WICKET-3269
> Project: Wicket
> Issue Type: Improvement
> Components: wicket
> Affects Versions: 1.5-M3
> Reporter: Sven Meier
> Assignee: Igor Vaynberg
> Attachments: AbstractTextComponent_A.diff,
> AbstractTextComponent_B.diff, WICKET-3269-test.patch, WICKET-3269.patch
>
>
> Context:
> With convertEmptyInputStringToNull set to 'true' (the default),
> AbstractTextComponent converts empty strings to 'null'.
> This works only if the component doesn't know its model type.
> Problem:
> In our application we would like to always keep empty Strings as they are. We
> tried to use a ComponentInstantiationListener to set
> convertEmptyInputStringToNull to 'false', but regretfully
> AbstractTextComponent reverts this setting to 'true' in its constructor.
> Proposals for 1.5 (either A or B):
> A) Change default of convertEmptyInputStringToNull to 'false'.
> - allows applications to keep empty strings as they are,
> - if needed, clients can use a ComponentInstantiationListener to globally set
> convertEmptyInputStringToNull to 'true' for the old default
> B) Remove support for special handling of empty strings.
> - no special handling in #convertValue(String[]) and #resolveType() needed,
> - no more ambiguity whether ConvertEmptyInputStringToNull has any effect
> (model type known or not),
> - if needed, clients can use a custom Converter to convert empty strings to
> 'null'.
> See attached patches, note that no unit tests changes were required.
> Thanks for your consideration.
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