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https://issues.apache.org/jira/browse/ISIS-2575?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17300438#comment-17300438
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Andi Huber commented on ISIS-2575:
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Very high level quality feedback. Thanks for that! Certainly going to look into
it, if it can be fixed that easily.
> PanelAbstract found to be suspectious generic by the IDE because of erasure
> clash.
> ----------------------------------------------------------------------------------
>
> Key: ISIS-2575
> URL: https://issues.apache.org/jira/browse/ISIS-2575
> Project: Isis
> Issue Type: Improvement
> Components: Isis Viewer Wicket
> Affects Versions: 2.0.0-M3, 2.0.0-M4
> Environment: IntelliJ IDEA 2020.3.2 (Ultimate Edition)
> Build #IU-203.7148.57, built on January 26, 2021
> Runtime version: 11.0.9.1+11-b1145.77 amd64
> VM: OpenJDK 64-Bit Server VM by JetBrains s.r.o.
> Linux 5.8.0-44-generic
> GC: ParNew, ConcurrentMarkSweep
> Memory: 8083M
> Cores: 16
> Current Desktop: ubuntu:GNOME
> Reporter: Miklós Győrfi
> Priority: Minor
> Fix For: 2.0.0-M5
>
>
> Due to the generic handling of Wicket and Isis, there is an annoying error
> message in IDE (IntelliJ (IntelliJ IDEA 2020.3.2 (Ultimate Edition) Build
> #IU-203.7148.57) and Eclipse as well):
> {{'setDefaultModel(IModel model)' in 'org.apache.wicket.MarkupContainer'
> clashes with 'setDefaultModel(IModel model)' in
> 'org.apache.wicket.IGenericComponent'; both methods have same erasure yet
> neither overrides the other}}
> It is displayed on every class which is PanelAbstract descendant. The root
> cause is the generic-raw-generic inheritance tree branch: PanelAbstract is a
> generic parametrized by IModel, and its ancestor, PanelBase is originally a
> generic parametrized by the content of the IModel. Basically PanelAbstract
> should be declared as
> {code:java}
> class PanelAbstract<U, T extends IModel<U>> extends PanelBase<U> ...
> {code}
> Of course, this is inconvenient and repetitive, but Java can't infer U from
> T.
>
> So it is fair cause to use raw type in-the-middle to change, "unbox" the
> parameter. But this cause a huge mess in the IDE. Two ancestors of
> PanelAbstract has the same method: setDefaultModel in IGenericComponent<T,
> GenericPanel<T>> (which is generic, and the method is default) and
> MarkupContainer (which is NOT a generic) won't match any more, although their
> erasure won't be different: the compiler complains.
> There is a comment in PanelAbstract about this solution describing it
> suspectious.
> My suggestion to solve this problem:
> Simply make the PanelBase to be raw, using Panel instead of GenericPanel<T>:
> {code:java}
> public class PanelBase extends Panel implements HasCommonContext {
> {code}
>
>
> This simply solves the problem, and removes the generic-raw-generic ancestor
> tree mess (Panel and its ancestors are raw types), makes the inheritance
> cleaner.
> There are some places where PanelBase is used directly, but these can be
> solve easily as most of them are PanelBase<Void>.
>
> Other solution is to keep the generic:
> {code:java}
> public abstract class PanelAbstract<T extends IModel<?>>
> extends PanelBase<Object>
> {code}
> but getModel will return IModel<Object> which is not compatible to T of
> course, so we need another method, for example getPanelModel() which returns
> T. This need more refactoring, so I suggest the first.
>
>
> It is a minor problem, but very annoying to develop new PanelAbstract
> descendant, so I would be happy to see a solution.
>
> Some links, in connection with this problem:
> https://issues.apache.org/jira/browse/WICKET-6804
> https://stackoverflow.com/questions/51931500/wicket-8-wicket-setdefaultmodel-clashes-with-setdefaultmodel
>
>
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