[WICKET-2325] IChoiceRenderer generic type parameters are wrong throughout the AbstractChoice class hierarchy

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.4-RC5
• Fix Version/s: 1.4-RC6
• Component/s: wicket
• Assignee: Igor Vaynberg
• Reporter: Max Oliver Bowsher
• Created: 12/Jun/09 16:22
• Updated: 12/Jun/09 17:24
• Resolved: 12/Jun/09 17:24

Description

All the AbstractChoice components currently make use of an IChoiceRenderer<T>. They should more properly make use of an IChoiceRenderer<? super T>. The excessive strictness of the type parameter prevents users from defining a singleton choicerenderer that can be used for a variety of different choice components for different but related classes.

Example use-case: Most of my persistent beans implement INamedPersistentObject, providing getName() and getPrimaryKey() methods. This is enough to implement an IChoiceRenderer<INamedPersistentObject>. I wish to declare a singleton instance of this and reuse it for various choice components on various concrete types, but currently can't without messy casts.

I have set priority=blocker on this bug because it is an API issue which really needs consideration before 1.4 is released, as depending on how strict an API/ABI compatibility policy is used, it might be considered unfixable once 1.4 is released GA.