Apache Wicket 1.5 正式发布

Apache Wicket 团队正式发布了 Apache Wicket 1.5， 一个基于组件的开源 WEB 框架。Apache Wicket 1.5 经过两年的开发，与之前版本相比，带来无数的改进。

下载地址
-----------------------------
http://www.apache.org/dyn/closer.cgi/wicket/1.5.0

如果使用Maven，可以添加下面的代码到 POM 升级到最新版本:

 

<dependency>
    <groupId>org.apache.wicket</groupId>
    <artifactId>wicket-core</artifactId>
    <version>1.5.0</version>
</dependency>

 

值得注意的是，Wicket 的主 artifact ID 更名为 wicket-core。

你必须升级所有的模块(i.e. wicket, wicket-extensions,
wicket-ioc, wicket-spring, etc) 到1.5.0，在使用最新版本，不要混合使用之前的版本。

值得注意的变更
--------------------

这个发布版本中，Wicket 团队对其内部进行了大量的更新。包括：

- 添加了 HTML5 组件: EmailTextField, NumberTextField, UrlTextField and
   RangeTextField

- 全新的组件内事件机制 (下面会解释)

- servlet API 最低版本为 servlet-api 2.5

- 所有的标准的 validators 继承了 Behavior 以便客户端验证

- 删除 IBehavior，AbstractBehavior 标志为过时，现在你应该直接从 Behavior 继承。

- 简化请求生命周期处理，使其更有扩展性

- URL 集中处理

- Wicket’s rendering 代码大大简化

- 改进了浏览器缓存支持

- ClientSideImageMap 代替了旧的 ImageMap

- Better support for running behind proxies with x-forwarded-for header

- Request cycle listeners  使集成框架到你的 Wicket 应用中变得更加简单

-  一致的命名: 方法名的 Javascript 更名为 JavaScript

- 切换到 HTTPS 很简单，只配置一个新的 root mapper，让 Wicket 能够识别 HTTPS，在页面添加  @RequireHttps

更详细的变更和改进包含在升级指南中.

组件内部事件机制
----------------------

Wicket 1.5 offers a simple, yet flexible, way for component to communicate
with each other in a decoupled manner. The two major interfaces that
facilitate this are:

/**
* Objects that can send events
*/
public interface IEventSource {
     void send(IEventSink sink, Broadcast broadcast, T payload);
}

 
and

/**
* Objects that can receive events
*/
public interface IEventSink
{
    /**
     * Called when an event is sent to this sink
     */
    void onEvent(IEvent> event);
}

 
The classes that implement these interfaces, and can thus participate in the
event mechanism are: Component, RequestCycle, Session, and Application.

The mechanism allows for different event broadcast methods defined here:

/**
* Defines the event broadcast type.
*/
public enum Broadcast {
    BREADTH,
    DEPTH,
    BUBBLE,
    EXACT;
}

 
There is an example in wicket-examples which demonstrates the usage of this.

Applications can register custom event dispatchers in FrameworkSettings; the
dispatchers can be used to build custom event delivery mechanisms. For example
a custom IEventDispatcher mechanism can route events to annotated methods, for
example:

public class MyComponent extends Component {
    @OnEvent
    private void onUserAdded(UserAddedEvent event) {...}
}

 
where UserAddedEvent is the event payload object.

The default Component#onEvent method will be called even if custom dispatchers
are registered.

A default event is raised whenever Wicket begins to create an AJAX response.
The payload of the event is the AjaxRequestTarget used for event. Sample
implementation:

 

// component that always adds itself to the ajax response
public class MyComponent extends Component {
    public void onEvent(IEvent event) {
        if (event.getPayload() instanceof AjaxRequestTarget) {
            ((AjaxRequestTarget)event.getPayload()).add(this);
         }
    }
}