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https://issues.apache.org/jira/browse/WICKET-6569?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16585693#comment-16585693
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Michael Gerhards commented on WICKET-6569:
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The aim is to link the parent's default model with the child's default model.
If I would pass the actual model to the child component and later someone calls
"setDefaultModel" on the parent component, than the child component will not
notice and both models diverge.
I general for the user of a component, it is often not clear if the model which
was passed in the component's constructor is the same/equal to getDefaultModel
and a later change using setDefaultModel would not violate the component's
internal contract. But is letting the "setDefaultModel" throw in
InvalidOperationException really an option? Ignoring a new defaultModel would
be a side effect.
The problem is more a theoretical one than a practical one, I know that. My
main reason to open this issue was more about wondering that the compiler is
confused by the overloaded of the LambdaModel.of method. I want to let you know
about this problem. And the easiest quick fix is to not overload the method but
publish the same method (additionally) under a different name.
> LambdaModel.of overload is ambiguous
> ------------------------------------
>
> Key: WICKET-6569
> URL: https://issues.apache.org/jira/browse/WICKET-6569
> Project: Wicket
> Issue Type: Wish
> Components: wicket
> Affects Versions: 8.0.0
> Reporter: Michael Gerhards
> Priority: Minor
> Attachments: myproject.zip
>
> Original Estimate: 4h
> Remaining Estimate: 4h
>
> a method call of
> LambdaModel.of(this::getModelObject, this::setModelObject)
> refers to
> public static <X, R> IModel<R> of(IModel<X> target, SerializableFunction<X,
> R> getter)
> but should be
> public static <R> IModel<R> of(SerializableSupplier<R> getter,
> SerializableConsumer<R> setter)
> The problem is that IModel and SerializableSupplier have functionally the
> same interface:
> T getObject(); vs. T get();
>
> Background:
> The child component should share its default model object with its parent
> component's default model object. So if setDefaultModelObject is called on
> the parent component than the child component should also refer to the new
> value (and with versa).
>
> Workaround:
> public Parent(String wicektId, IModel<Role> roleModel) {
> IModel<Role> childRoleModel = new IModel<Role>() {
> @Override
> public Role getObject()
> { return Parent.this.getModelObject(); }
> @Override
> public void setObject(Role object)
> { Parent.this.setModelObject(object); }
> };
> add(new Child("child", childRoleModel));
> }
>
> Solution:
> The problem only exists because .of Method is overloaded. If both methods
> would have different names (or be in different classes) than the compiler
> would be fine.
>
> Please see attached files
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