THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
...
Deprecate org.apache.wicket.util.IProvider
Replace it with standard Java 8 java.util.function.Supplier<T> which is virtually identical.
IGenericComponent's setter methods now return the current instance for method chaining
All specialization classes return their type.
AjaxFallback** components now use java.util.Optional
All AjaxFallback** components and the containers which use internally AjaxFallback** components, like AjaxTabbedPanel, RatingPanel and TableTree, have been reworked to pass Optional<AjaxRequestTarget> instead of just AjaxRequestTarget to their onXyz() callback methods. This way the application developer should not forget to check that the AjaxRequestTarget is not null.
Behavior changes
FormComponentPanel delegates the call to #clearInput to its FormComponent children
FormComponent#clearInput() has been made non-final, so that now containers like FormComponentPanel could override this method and call #clearInput() on its children of type FormComponent.
Removals
...
IModel uses Java 8 default interface method for IDetachable#detach()
For convenience IModel class provides a do-nothing implementation of IDetachable#detach() method, so custom implementations are not required to implement it when not needed.
ResourceStreamResource now receives Attributes as a parameter to its #getResourceStream() method
For access to the response, the request and its parameters now ResourceStreamResource#getResourceStream() receives an instance of org.apache.wicket.request.resource.IResource.Attributes.
Provide serializable versions of java.util.function.(Supplier|Consumer|Function)
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 and org.apache.wicket.model.lambda.WicketFunction. 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.
Provide IModel implementations which make use of Java 8 lambdas and method references
Wicket provides three new implementations of IModel which use Java 8 consumers and suppliers, i.e. may be used with lambda or method references.
org.apache.wicket.model.lambda.LambdaModel.
Code Block language java title LambdaModel collapse true Person person = ...; IModel<String> personNameModel = new LambdaModel<>( () -> person.getName(), (name) -> person.setName(name));org.apache.wicket.model.lambda.SupplierModel. It is similar to org.apache.wicket.model.AbstractReadOnlyModel.
Code Block language java title SupplierModel collapse true Person person = ...; IModel<String> personNameModel = new SupplierModel<>(person::getName);
org.apache.wicket.model.lambda.SupplierCachingModel. It is similar to org.apache.wicket.model.LoadableDetachableModel
Code Block language java title SupplierCachingModel collapse true Person person = ...; IModel<String> personNameModel = new SupplierCachingModel<>(person::getName);
IGenericComponent is a mixin/trait interface
IGenericComponent uses Java 8 default methods to implement #setModel(IModel<T>), #getModel(), #setModelObject(T) and #getModelObject() by delegating to the respective get/setDefaultModel[Object] methods.
This way it could be easily used by any Component by just implementing it.
...