[WICKET-3269] Review AbstractTextComponent's handling of empty Strings in 1.5

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Won't Fix
• Affects Version/s: 1.5-M3
• Component/s: wicket
• Assignee: Igor Vaynberg
• Reporter: Sven Meier
• Created: 18/Dec/10 15:09
• Updated: 03/Jan/11 18:57
• Resolved: 29/Dec/10 18:43

Description

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.