GWT多态列表与@ExtraTypes [英] GWT polymorphic lists with @ExtraTypes

问题描述

我有一个列表包含不同类型的元素有点问题，我想看看你之前是否有人遇到过这个问题。这个问题应该使用@ExtraTypes解决，但它不适合我，所以我想我没有正确使用它。所以，情况是（为了清楚起见，bean名称被改变了）：

概述：

• 使用GWT 2.5与RequestFactory。

SERVER-SIDE：

• 我有一个RootBean，其中包含

   List< ChildBean> 

  。



• 这个ChildBean包含一些原始属性。


• ChildBean也由一个继承所有父属性并添加更多内容的MoreSpecificChildBean扩展。根据一些逻辑，RootBean根据类型为ChildBean和MoreSpecificChildBean的元素获取列表。

CLIENT-SIDE：

• IRootBeanProxy是一个带有以下注解的ValueProxy：
  
  

   
   @ProxyFor（value = RootBean.class）
   @ExtraTypes（{IMoreSpecificChildBeanProxy.class}）
   

并包含列表

列表< IChi ldBeanProxy> getChildren（）; 

• IChildBeanProxy是一个ValueProxy：
  

   
   @ProxyFor（value = ChildBean）
   public interface IChildBeanProxy extends ValueProxy 
   



• IMoreSpecificChildBeanProxy是一个ValueProxy：
  

   
   @ProxyFor（value = MoreSpecificChildBean）
   public interface IMoreSpecificChildBeanProxy extends IChildBeanProxy 
   



• 请求上下文有一个返回Request的方法，我也在这里添加了@ExtraTypes注释：
  

   
   @Service（value = CompareService.class，locator = SpringServiceLocator.class）
   @ ExtraTypes（{IChildBeanProxy.class，IMoreSpecificChildBeanProxy.class}）
   public interface ICompareRequestContext extends RequestContext {
   Request< IRootBeanProxy>比较（Integer id1，Integer id2）; 
   

问题

假设有了这些注释，RF应该知道多态继承类的存在，但我在客户端获得的是一个IRootBeanProxy，其中包含IChildBeanProxy元素的列表。此列表包含MoreSpecificChildBean，但是采用IChildBeanProxy的形式，所以我无法从其他人那里得知它。
所以我想知道我做错了什么，如果我在错误的地方或其他地方设置了ExtraTypes注释。

任何人？

所有的帮助!!

解决方案

几个类，但它总是会返回我可以迭代的基本类型，并在需要时测试instanceof。您可能必须将对象投射到子类。如果您不添加@ExtraTypes，您将会知道，因为在服务器端，您将收到一条消息，指出MoreSpecificChildBean无法发送到客户端。

我只注释了服务而不是代理，我遇到了一些怪异的情况，并在代理中添加了@ExtraTypes。

  / ** 
 *所有其他指标代理扩展的基本代理。它主要用于
 *继承RequestFactory。具体实现是
 * {@link MetricNumber}。 
 * 
 * @author chinshaw 
 * / 
 @ProxyFor（value = Metric.class，locator = IMetricEntityLocator.class）
 public interface MetricProxy extends DatastoreObjectProxy {
 
 
 / ** 
 *此对象的名称在ui中。这通常会被
 *子类扩展。 
 * / 
 public String NAME =Generic Metric; 
 
 / ** 
 *这是ui可以支持的输出类型列表。这是
 *通常用于在操作
 *输出屏幕中列出支持的度量标准类型。 
 * 
 * @author chinshaw 
 * / 
 public enum MetricOutputType {
 MetricNumber，MetricString，MetricCollection，MetricStaticChart，MetricDynamicChart 
} 
 
 / ** 
 *请参阅{@link MetricNumber＃setName（String）} 
 * 
 * @param name 
 * / 
 public void setName（String名称）; 
 
 / ** 
 *请参阅MetricNumber＃setContext（String）} 
 * 
 * @return指标的名称。 
 * / 
 public String getName（）; 
 
 
 / ** 
 *获取附加到该指标的违规列表。 
 * 
 * @return 
 * / 
 public List< ViolationProxy> getViolations（）; 
} 
 
 @ProxyFor（value = MetricNumber.class，locator = IMetricEntityLocator.class）
 public interface MetricNumberProxy extends MetricProxy {
 
 public List< NumberRangeProxy> ; getRanges（）; 
 
 public void setRanges（List< NumberRangeProxy> ranges）; 
 
  

...

  @ProxyFor（value = MetricDouble.class，locator = IMetricEntityLocator.class）
 public interface MetricDoubleProxy extends MetricNumberProxy {
 $ b $ / * *用于子句的对象* / 
 public static String [] PROPERTIES = {ranges}; 
 
 public Double getValue（）; 
 
  

...

  @ProxyFor（value = MetricPlot.class，locator = IMetricEntityLocator.class）
 public interface MetricPlotProxy extends MetricProxy {
 
 / ** 
 * UI对象的名称。 
 * / 
 public String NAME =Static Plot; 
 
 public String getPlotUrl（）; 
 
 
 
 $ b $ p 
 $ b这是一种编制方法，因为我通常总是返回复合类，包含一系列指标。这就是说，这将返回我基础类型的指标，然后我可以投它们。
 
 $ p $  @ExtraTypes（{MetricProxy。类，MetricNumberProxy.class，MetricDoubleProxy.class，MetricIntegerProxy.class}）
 @Service（value = AnalyticsOperationDao.class，locator = DaoServiceLocator.class）
 public interface AnalyticsOperationRequest扩展DaoRequest< AnalyticsOperationProxy> {
 
请求<列表<< MetricProxy>> getSomeMetrics（）; 
  

}

不是一个确切的方法I使用，但将用于获取类型的代理。

  context.getSomeMetrics（）。with（MetricNumber.PROPERTIES）.fire （MetricProxy度量标准）{
 if（metric）{
 
 $ b public void onSuccess（List< MetricProxy> metrics）{
 （MetricDoubleProxy）{
 logger.info（有一双double+ metric.getValue（））; 
} 
} 
} 
} 
  

您会知道在出现上述错误时是否缺少@ExtraTypes注释。

希望有帮助

I have a little problem with a list that contains different types of elements and i would like to see if anyone of you have met the problem before. The issue should be solved with the use of @ExtraTypes, but it is not working for me, so i guess i am not using it correctly. So, the scenario is (bean names are changed for clarity):

GENERAL:

• I am using GWT 2.5 with RequestFactory.

SERVER-SIDE:

• I have a RootBean that contains, among other stuff, a

  List <ChildBean>

  .

• This ChildBean contains some primitive attributes.
• ChildBean is also extended by a MoreSpecificChildBean that inherits all the parent attributes and adds a few more.
• The RootBean gets its list filled up with elements of type ChildBean and MoreSpecificChildBean depending on some logic.

CLIENT-SIDE:

• IRootBeanProxy is a ValueProxy with these annotations:

   @ProxyFor (value = RootBean.class)
   @ExtraTypes ({IMoreSpecificChildBeanProxy.class})
  

and contains a list

List <IChildBeanProxy> getChildren ();

• IChildBeanProxy is a ValueProxy:

  @ProxyFor (value=ChildBean)
  public interface IChildBeanProxy extends ValueProxy
  

• IMoreSpecificChildBeanProxy is a ValueProxy:

  @ProxyFor (value=MoreSpecificChildBean)
  public interface IMoreSpecificChildBeanProxy extends IChildBeanProxy
  

• the Request context has a method that returns Request and i added the @ExtraTypes annotation here too:

  @Service (value = CompareService.class, locator = SpringServiceLocator.class)
  @ExtraTypes ({IChildBeanProxy.class, IMoreSpecificChildBeanProxy.class})
  public interface ICompareRequestContext extends RequestContext {
     Request <IRootBeanProxy> compare (Integer id1, Integer id2);
  

Question

Supposedly with those annotations, RF should be aware of the existence of polymorphic inherited classes, but all i get in the client is an IRootBeanProxy with a list of IChildBeanProxy elements. This list includes the MoreSpecificChildBean, but in the shape of a IChildBeanProxy, so that i cannot tell it from the others. So i am wondering what i am doing wrong, if i am setting the ExtraTypes annotation at the wrong place or something.

Anyone?

Thx for all the help!!

解决方案

I do the exact same thing for quite a few classes but it will always return me the base type which I can iterate through and test for instanceof if needed. You will probably have to cast the object to the subclass. If you do not add the @ExtraTypes you will know because on the server side you will get a message stating that MoreSpecificChildBean cannot be sent to the client.

I only annotate the service and not the proxy, I ran into some quirks with 2.4 adding @ExtraTypes to the proxy.

/**
 * Base proxy that all other metric proxies extend. It is used mainly for it's
 * inheritence with the RequestFactory. It's concrete implementation is
 * {@link MetricNumber}.
 * 
 * @author chinshaw
 */
@ProxyFor(value = Metric.class, locator = IMetricEntityLocator.class)
public interface MetricProxy extends DatastoreObjectProxy {


    /**
     * Name of this object in the ui. This will commonly be extended by
     * subclasses.
     */
    public String NAME = "Generic Metric";

    /**
     * This is a list of types of outputs that the ui can support. This is
     * typically used for listing types of supported Metrics in the operation
     * output screen.
     * 
     * @author chinshaw
     */
    public enum MetricOutputType {
        MetricNumber, MetricString, MetricCollection, MetricStaticChart, MetricDynamicChart
    }

    /**
     * See {@link MetricNumber#setName(String)}
     * 
     * @param name
     */
    public void setName(String name);

    /**
     * See {@link MetricNumber#setContext(String)}
     * 
     * @return name of the metric.
     */
    public String getName();


    /**
     * Get the list of violations attached to this metric.
     * 
     * @return
     */
    public List<ViolationProxy> getViolations();
}

@ProxyFor(value = MetricNumber.class, locator = IMetricEntityLocator.class)
public interface MetricNumberProxy extends MetricProxy {

    public List<NumberRangeProxy> getRanges();

    public void setRanges(List<NumberRangeProxy> ranges);
}

...

@ProxyFor(value = MetricDouble.class, locator = IMetricEntityLocator.class)
public interface MetricDoubleProxy extends MetricNumberProxy {

    /* Properties when fetching the object for with clause */
    public static String[] PROPERTIES = {"ranges"};

    public Double getValue();
}

...

@ProxyFor(value = MetricPlot.class, locator = IMetricEntityLocator.class)
public interface MetricPlotProxy extends MetricProxy {

    /**
     * UI Name of the object.
     */
    public String NAME = "Static Plot";

    public String getPlotUrl();
}

This is a made up method from because I usually always return composite classes that may contain a list of metrics. That being said this will return me the base type of metrics, and then I can cast them.

@ExtraTypes({ MetricProxy.class, MetricNumberProxy.class, MetricDoubleProxy.class, MetricIntegerProxy.class})
@Service(value = AnalyticsOperationDao.class, locator = DaoServiceLocator.class)
public interface AnalyticsOperationRequest extends DaoRequest<AnalyticsOperationProxy> {

    Request<List<<MetricProxy>> getSomeMetrics();

}

Not an exact method I use but will work for getting a proxy of type.

context.getSomeMetrics().with(MetricNumber.PROPERTIES).fire(new Receiver<List<MetricProxy>>() {

  public void onSuccess(List<MetricProxy> metrics) {
      for (MetricProxy metric : metrics) {
          if (metric instanceof MetricDoubleProxy) {
              logger.info("Got a class of double " + metric.getValue());
          }
      }          
  }
}

You will know if you are missing an @ExtraTypes annotation when you get the error stated above.

Hope that helps

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