Migrating to Wicket 7.0

Environment

Wicket 7.0 requires at least Java 7

Wicket 7.0 requires Servlet 3.0

The HTTP response is not flushed automatically when the request is started in asynchronous mode. WICKET-5152

This is an improvement in Wicket 7.0 which should not affect any application migrating from Wicket 6.x. But if you use Servlet 3.0's AsyncContext in IResource in Wicket 7 then make sure that your code flushes the http response after completing the request.

API changes

org/apache/wicket/core/util/io/SerializableChecker is replaced with org.apache.wicket.core.util.objects.checker.CheckingObjectOutputStream WICKET-4817

CheckingObjectOutputStream accepts a list of org.apache.wicket.core.util.objects.checker.IObjectChecker objects which are used to check for different kind of problems during object serialization. Commit diff: d0441059e0

org/apache/wicket/markup/html/border/BoxBorder is removed with no replacement WICKET-4966.

BoxBorder class has been deprecated in Wicket 6.x series

org.apache.wicket.Component#renderHead(HtmlHeaderContainer) is renamed to Component#internalRenderHead(HtmlHeaderContainer) WICKET-4964

Component#renderHead(HtmlHeaderContainer) was very similar to the usually used Component#renderHead(IHeaderResponse). So it has been renamed to avoid any confusions.

org.apache.wicket.request.resource.ResourceReference#getDependencies() now returns a mutable List<HeaderItem> WICKET-5124

The old API returned Iterable<? extends HeaderItem> and was inconvenient to override and add additional dependencies.
With the new API it is as easy as:

@Override
public List<HeaderItem> getDependencies() {
  List<HeaderItem> dependencies = super.getDependencies();
  dependencies.add(dep1);
  dependencies.add(dep2);
  return dependencies;
}

The same is done for org.apache.wicket.markup.head.HeaderItem#getDependencies() too.

org.apache.wicket.model.StringResourceModel constructor accepts IModel<String> for its default value WICKET-4972

There were two problems with the old way:

• since the parameters argument type is Object..., i.e. varargs, it was hard for the compiler and runtime to differentiate the "defaultValue" from the "parameters"
• it wasn't possible to use lazy evaluation of the default value

If in your application you have code like:

StringResourceModel model = new StringResourceModel(resourceKey, model, "Some default value", new Object[] [param1, param2]);

then the simplest solution is to use Model.of("Some default value"):

StringResourceModel model = new StringResourceModel(resourceKey, model, Model.of("Some default value"), new Object[] [param1, param2]);

org.apache.wicket.extensions.validation.validator.+Xyz+Validator#decorate() now works with IValidationError WICKET-5174

This method now accepts IValidationError as an argument and returns IValidationError. This way it can be used with other IValidationError implementations like RawValidationError for example.

org.apache.wicket.ajax.attributes.AjaxRequestAttributes#setAllowDefault is renamed to #setPreventDefault WICKET-5197

This is done to make it more consistent with JavaScript API.

Behavior changes

org.apache.wicket.request.Url#getQueryString WICKET-4664

Url#getQueryString() now behaves as HttpServletRequest behaves :

• returns the query string without the leading "?"
• returns null when there is no query string

RequestUtils#decodeParameters() now strips the "?" from the output value.

org.apache.wicket.request.http.WebResponse encodes the value of the "filename" in Content-Disposition header WICKET-4934

The value of the file name used in "Content-Disposition" response header can contain characters which should be encoded

org.apache.wicket.markup.html.form.FormComponentLabel outputs "required", "disabled" and "error" classes when its form component is either required, disabled or invalid. WICKET-5177

This way it is in sync with AutoLabel (the auto component that is used for "wicket:for" attribute).

org.apache.wicket.markup.html.panel.FeedbackPanel Do not set CSS class on the li > span element for a feedback message WICKET-4831

The css class is now only applied to the li element and not to the span inside. Additionally a FeedbackPanel#newMessageItem() method has been added to allow customization of each feedback message item (similar to DataTable#newRowItem()).

AjaxEventBehavior doesn't prevent the default behavior of the JavaScript event WICKET-5197

From now on only AjaxFallback** components prevent the default JavaScript event behavior so only the Ajax call is made when JavaScript is enabled in the browser.
If the default behavior should be prevented in any use case then use:

attributes.setPreventDefault(true);

Dependency updates

All libraries on which Wicket modules depend are updated to their latest stable versions.
The most notable ones are:

• Spring Framework 3.2.2
• ASM 4.1
• CGLIB 3.0
• SLF4J 1.7.5
• Jetty (in the quickstart) 8.1.10