On Thu, Feb 12, 2009 at 10:17 AM, Paul Sandoz <Paul.Sandoz_at_sun.com> wrote:
>
> On Feb 12, 2009, at 12:46 AM, Denis AH-KANG wrote:
>
> Hi all,
>>
>> I have some questions about the jersey client and its exceptions.
>> Why does the client only throw runtime exceptions (ClientHandlerException
>> and
>> UniformInterfaceException)?
>>
>>
>
> ClientHandlerException is thrown is there is an error reading/writing the
> response e.g. an IOException.
>
> UniformInterfaceException is thrown when status code of the HTTP response
> indicates a response that is not expected. And in your example below you
> need to refer to UniformInterfaceException.
>
Actually, the problem is that these exceptions extend a runtime exception
and Java typechecking doesn't force to catch that kind of exceptions.
According to me, HTTP errors must be mapped to java exception that we have
to deal with (e.g. force catching).
That article
http://scv.bu.edu/Doc/Java/tutorial/java/exceptions/runtime.html shows you
what i think.
>
>
>
> Actually, I need to use the client and manage the most common HTTP
>> responses (400, 404, 500...).
>> For the moment, I catch the client exception and get the status code from
>> it. It means I need
>> to create a switch case to handle each case. For instance:
>>
>> catch(ClientHandlerException e) {
>> switch(e.getResponse().getResponseStatus()):
>> case 400:
>> //some code
>> case 404:
>> //some code
>> ....
>> }
>>
>> Do you know if there's a better way to use the jersey client?
>>
>>
> The approach taken by the client API is by default to handle common cases
> are not considered exceptional and uncommon cases like response errors as
> exception cases.
>
> So if i do a:
>
> String s = resource.get(String.class)
>
> then a UniformInterfaceException will be thrown if the response has a
> status code >= 300 and the response contains no entity.
>
> If you do this:
>
> ClientResponse r = resource.get(ClientResponse.class);
>
> then UniformInterfaceException will not be thrown. And it is up to you to
> handle the response status in normal code blocks, for example:
>
> ClientResponse r = resource.get(ClientResponse.class);
> switch(r.getResponseStatus()):
> case 400:
> //some code
> case 404:
> //some code
> ....
> }
>
> See the JavaDoc for more details:
>
>
> https://jersey.dev.java.net/source/browse/*checkout*/jersey/tags/jersey-1.0.1/api/jersey/com/sun/jersey/api/client/UniformInterface.html
Don't you think it'll useful to extends the UniformInterfaceExceptions for
the common HTTP error codes?
For instance:
try {
...
} catch (NotFoundException nfe) {
//HTTP 404
} catch (InternalSystemException ise) {
// HTTP 500
} catch (UniformInterfaceException)
// Don't need to use getResponseStatus: typechecking has already given
the information
}
If you agree, I can contribute on this part.
>
>
> Paul.
>
>
>