Migration to Wicket 8.0

Replace IContextProvider<T, C> with standard Java 8 java.util.function.Function<C, T> which is virtually identical.

As a consequence IPageManagerProvider, IPageRendererProvider and IRequestCycleProvider now override #apply() method instead of #get().

Deprecate org.apache.wicket.protocol.http.documentvalidation.HtmlDocumentValidator  WICKET-6119 - Getting issue details... STATUS

Tests based on HtmlDocumentValidator are very fragile. They start to fail as soon as there is a single character change somewhere in the page markup.

We believe that there are very few users of this API. It is recommended to use TagTester and WicketTestCase#executeTest() instead.

Deprecate org.apache.wicket.model.AbstractReadOnlyModel

Use an anonymous instance of IModel instead. Since Wicket 8.0 IModel doesn't require providing implementation of #setObject(Object) method.

AbstractChoice#getChoices() has been made final. If the application needs to provide different choices for each render then it should override AbstractChoice#getChoicesModel() instead. The application code would be almost the same as before, it will just need to wrap the final List result in an IModel, most probably ListModel.

ListenerInterfaceRequestHandler simplification WICKET-6137 - Getting issue details... STATUS

RequestListenerInterface was removed:

• IResourceListener, IBehaviorListener, IOnChangeListener, ILinkListener are replaced by the generic method IRequestListener#onRequest()
• ListenerInterfaceRequestHandler was renamed to ListenerRequestHandler
• Component's and Behavior's #canCallListenerInterface() were renamed to #canCallListener()
• PageSettings#getCallListenerInterfaceAfterExpiry() was renamed to #getCallListenerAfterExpiry.

A Component or Behavior can now implement IRequestListener once only, thus removing the need to include an identifier (e.g. "ILinkListener") in the URL.

wantOnSelectionChangedNotifications moved to FormComponentUpdatingBehavior  WICKET-6348 - Getting issue details... STATUS

Change notification was moved from CheckBox, DropDownChoice, RadioChoice, CheckGroup/Check and RadioGroup/Radio into a new behavior FormComponentUpdatingBehavior.

Instead of subclasses the component, this behavior can now be added to the component:

// Wicket 7.x
new CheckBox("id", model) {
	protected boolean wantOnSelectionChangedNotifications() {
		return true;
        }

	protected void onSelectionChanged(Boolean newSelection) {
		// do something, page will be rerendered;
	}
};


// Wicket 8.x
new CheckBox("id", model)
.add(new FormComponentUpdatingBehavior() {
	protected void onUpdate() {
		// do something, page will be rerendered;
	}

    protected void onError(RuntimeException ex) {
        super.onError(ex);
    }
});

As with AjaxFormComponentUpdatingBehavior any error during processing of the form component can now be handled in #onError().

Renderers are IDetachable now  WICKET-6347 - Getting issue details... STATUS

Renderers (IChoiceRendere, IOptionRenderer and IAutoCompleteRenderer now take part in detachment as other Wicket concepts like components and models. The owning component is responsible to detach it.

By using org.apache.wicket.resource.DynamicJQueryResourceReference Wicket will contribute jQuery ver. 2.x for modern browsers and ver. 1.x when the request is done by Internet Explorer older than ver. 9.

AuthenticatedWebSession#singOut() now is an alias of Session#invalidate()  WICKET-6228 - Getting issue details... STATUS

The old behavior of #signOut() didn't bring much value and caused confusion to some users. Now it is just an alias of Session#invalidate().

SecuritySettings#enforceMounts(true) now disables BookmarkableMapper   WICKET-6161 - Getting issue details... STATUS

If this setting is enabled then a page could not be requested via /wicket/bookmarkable/com.example.PageName. A page has to be explicitly mounted at MyApplication#init() to be able to request it.

WicketObjects#sizeof() and #cloneObject() should not use IObjectCheckers   WICKET-6334 - Getting issue details... STATUS

WicketObjects#cloneObject() and #sizeof() now create a new instance of JavaSerializer to clone or take the size of an object respectively.

If the configured ISerializer in the IFrameworkSettings is not an instance of JavaSerializer then it is used as is!

StatelessChecker throws StatelessCheckFailureException (a WicketRuntimeException) instead of IllegalStateException     WICKET-6343 - Getting issue details... STATUS

StatelessChecker now provides an overrideable method named #fail() that accepts an instance of StatelessCheckFailureException. This method is being called

For convenience IRequestHandler class provides a do-nothing implementation of its #detach() method, so custom implementations are not required to implement it when not needed.

For access to the response, the request and its parameters now ResourceStreamResource#getResourceStream() receives an instance of org.apache.wicket.request.resource.IResource.Attributes.

java.util.function.Consumer and other classes are not serializable and this makes them unusable in stateful Wicket pages. For this reason Wicket provides org.apache.wicket.model.lambda.WicketSupplier, org.apache.wicket.model.lambda.WicketConsumer, org.apache.wicket.model.lambda.WicketFunction and org.apache.wicket.model.lambda.WicketBiFunction. Those interfaces should be used in method signatures where Java 8 lambdas or method references could be used. At the call site there is nothing specific to be done, i.e. just use lambdas and method references without any casting.