Add nullSafeConverter method to Converter interface

[peholmst]

Description

When writing converters, there are already methods provided for using mapper functions that map between the model and presentation values. This is useful, but these functions, like LocalDate::parse or LocalDate::toString always assume a non-null input. Since converters work with both null inputs and outputs, you virtually always have to write your own custom validators to handle nulls.

This helper function allows you to write converters like this:

Converter<String, LocalDate> converter = Converter.nullSafeConverter(
    Converter.from(LocalDate::parse, LocalDate::toString, Exception::getMessage)
);

Type of change

• Bugfix
• Feature

[sonarqubecloud]

Quality Gate passed

Issues
2977 New issues
1 Accepted issue

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

Test Results

 1 389 files  + 58   1 389 suites  +58   1h 25m 42s ⏱️ +21s
 9 935 tests +667   9 864 ✅ +668  71 💤 ±0  0 ❌  - 1 
10 408 runs  +667  10 328 ✅ +668  80 💤 ±0  0 ❌  - 1 

Results for commit 940caa8. ± Comparison against base commit e1dd8c3.

[peholmst]

Converting back to draft. This needs some more work with regards to empty values. For some fields, the empty value is not null.