[jira] [Created] (WICKET-5846) Widen generic definition on AbstractRangeValidator

["Andrew Geery (JIRA)" <ji...@apache.org>]

Andrew Geery created WICKET-5846:
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             Summary: Widen generic definition on AbstractRangeValidator 
                 Key: WICKET-5846
                 URL: https://issues.apache.org/jira/browse/WICKET-5846
             Project: Wicket
          Issue Type: Improvement
          Components: wicket
    Affects Versions: 7.0.0-M5
            Reporter: Andrew Geery
            Priority: Minor


I ran into a problem extending {{org.apache.wicket.validation.validator.AbstractRangeValidator}} to work with {{java.time.LocalDate}} in Java 8.

The problem is the generic R parameter in {{AbstractRangeValidator}}:

{code:java}
public abstract class AbstractRangeValidator<R extends Comparable<R> & Serializable, V extends Serializable> { ... }
{code}

The issue is that while {{LocalDate}} is both {{Serializable}} and {{Comparable}}, it doesn't implement {{Comparable<LocalDate>}}, as required by {{AbstractRangeValidator}}.  Instead, it implements {{Comparable<ChronoLocalDate>}}.

In order to get {{AbstractRangeValidator}} to work with {{LocalDate}}, we need to relax/widen the definition of R to extend Comparable that is bound to a super of R:

{code:java}
public abstract class AbstractRangeValidator<R extends Comparable<? super R> & Serializable, V extends Serializable>
{code}

As this definition is slightly wider than the previous definition, all previous uses will continue to be valid.  The advantage to making this change is that it allows the {{AbstractRangeValidator}} to work with other classes like {{LocalDate}}.



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