在GWT客户端接收来自Restlet Framework的自定义异常 [英] Receive custom exceptions from Restlet Framework in GWT client

问题描述

我想使用Restlet Framework和GWT客户端的异常处理。
Restlet框架支持本文中描述的注释异常的概念;

 私人类PostLocationCallback实现了AsyncCallback< LocationDto> 
 {
 ... 
 
 @Override 
 public void onFailure（Throwable pCaught）
 {
 mCallback.onFailure（pCaught，mLocationDto） ; 
 
 
 
 
 
 
 $ b 
但是参数pCaught只包含一个ResourceException和状态码
 My LocationNameException不包含在基础原因堆栈中。 
我需要此LocationNameException来处理适当的错误消息。 
 
 $ b 
原因是Restlet GWT ClientProxyGenerator生成的ServerResourceProxy LocationListServerResourceProxyImpl; 
 
 
  public void postLocation（LocationDto param1，final LocationDto> callback）
 {
 ... 
 
 public void handle（Request request，Response response）
 {
 if（getClientResource（）。getStatus（）。isError（））
 {
 callback.onFailure（new ResourceException（getClientResource（）。getStatus（）））; 
} 
 else 
 {
 
 ... 
 
} 
  
我想我必须重写ClientProxyGenerator中的Post方法;  
 
 
  
 
 
 
 LocationNameException存在于响应数据中，因此 
 
 
 
只需在界面中指定例外ServerResourceProxy（ClientProxy）
 
 
 
  
 
 
 
和voilà
 p> 
 
 
  
 
 
 
  
 
 
 
可以在您的项目中立即使用此自定义ClientProxyGenerator（）。
 
 
 
  
 
 
 
在GWT模块XML中，将ClientProxyGenerator更改为服务器上的新版本; 
 
 
 
  
 
 
 
您已准备好使用您的自定义例外，但它会是不错，如果这个扩展将是整合在Restlet框架中。
 
I want to use Exception handling with the Restlet Framework and GWT clients.
The Restlet Framework supports the concept of annotated exceptions as described in this post;

http://restlet.com/company/blog/2015/12/21/exception-handling-with-restlet-framework/

In my project i created a LocationNameException
@Status(value = 409)
public class LocationNameException extends Exception
{
    ...

    ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
    public LocationNameException(String pMessage, Throwable pCause)
    {
        super(pMessage, pCause);
    }
}
And use this in my ServerResource;
   @Override
    @Transactional(rollbackOn = LocationNameException.class)
    public LocationDto postLocation(LocationDto pLocationDto) throws LocationNameException
    {
        ...

        Location lLocation = new Location(pLocationDto);

        try
        {
            LocationDao lLocationDao = getLocationDao();
            lLocationDao.persist(lLocation);
        }
        catch (PersistenceException pPersistenceException)
        {
            throw new LocationNameException("Location requires unique Name", pPersistenceException);
        }

        ...

        return lLocationDto;
    }
With the interface
public interface LocationListServerResourceInt
{
    ...

    @Post
    LocationDto postLocation(LocationDto pLocationDto) throws LocationNameException;

    ...
}  
This works, in the case of an exception the call returns code 409;



And at the GWT client side onFailure() is called;
private class PostLocationCallback implements AsyncCallback<LocationDto>
{
    ...

    @Override
    public void onFailure(Throwable pCaught)
    {
        mCallback.onFailure(pCaught, mLocationDto);
    }
}
But parameter pCaught only contains a ResourceException with the status code 409.
My LocationNameException isn't included in the underlying cause stack.
I need this LocationNameException for appropriate error message handling. 

The reason is the generated ServerResourceProxy  LocationListServerResourceProxyImpl by the Restlet GWT ClientProxyGenerator;
public void postLocation(LocationDto param1, final LocationDto> callback)
{       
    ...

    public void handle(Request request, Response response)
    {
       if (getClientResource().getStatus().isError())
       {       
          callback.onFailure(new ResourceException(getClientResource().getStatus()));
       }
       else
       {

    ...

}
I think i have to rewrite the Post method in the ClientProxyGenerator;



The LocationNameException is present in the Response data so the Basic approach using the getResponseEntity() method of the ClientResource class should be possible.

Is this the way to go? Or can i catch the LocationNameException exception somewhere else as suggested by Catching annotated exceptions?

It is really hard to try a different approach because of the generated code. Is there an easy way to circumvent the code generator with custom classes?  
解决方案
With help of Jerome Louvel and Thierry Boileau i created a new ClientProxyGenerator() that supports custom exceptions towards a GWT client;



Just specify the exception from the interface in the ServerResourceProxy (ClientProxy)



and voilà





It is possible to use this custom ClientProxyGenerator() in your project right away.

Download custom ClientProxyGenerator

And place it in a package on the server (for example package com.ludus.server.util)



In GWT module XML change the ClientProxyGenerator to the new version on the server;



And you're ready to go with your custom exceptions, but it would be nice if this extension would be integrated in the Restlet framework.

                        
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