On Nov 2, 2007, at 5:50 PM, Ryan J. McDonough wrote:
> My apologies for the multiple posts of my first message. GMails IMAP
> appears to be very flakey. But I think I got it now. So the proper
> syntax for this class would be:
>
> @Provider
> @Contract
There's no @Contract, that goes on the definition of EntityProvider.
>
> @ConsumeMime("image/jpg,image/png,image/gif")
> @ProduceMime("image/jpg,image/png,image/gif")
> public class ImageEntityProvider implements EntityProvider<IIOImage> {
>
> public IIOImage readFrom(Class<IIOImage> type,
> MediaType mediaType,
> MultivaluedMap<String, String> httpHeaders,
> InputStream entityStream) throws IOException {...}
>
> public void writeTo(IIOImage image,
> MediaType mediaTypes,
> MultivaluedMap<String, Object> httpHeaders,
> OutputStream entityStream) throws IOException {...}
>
> public boolean supports(Class<?> type) {...}
>
>
> Now I were using Jersey as an implementation, the
> AbstractTypeEntityProvider class would be annotated by an @Contract
> annotation. If ImageEntityProvider extended,
> AbstractTypeEntityProvider then ImageEntityProvider would not need
> to be marked with @Contract? I'm still a bit fuzzy on the need for
> @Contract both and @Provider. Couldn't @Provider just be sufficient?
>
Exactly, you put @Provider on an impl class, @Contract on an interface
or abstract class that defines the contract to be implemented. So you
don't need @Contract on either AbstractTypeEntityProvider or
ImageEntityProvider, it just goes on EntityProvider.
Marc.
>
> On Nov 2, 2007, at 10:58 AM, Marc Hadley wrote:
>
>> On Nov 2, 2007, at 9:55 AM, Ryan J. McDonough wrote:
>>
>>> As I read through some the spec and some of the Jersey code, I am
>>> not clear on how the proper syntax on how to create a custom
>>> EntityProvider. To help clarify my understanding, I have some code
>>> below for a theoretical ImageEntityProvider which would be able to
>>> render an Image representation. Based on what I have read so far,
>>> this is my understanding so far on how to implement it:
>>>
>>> @Provider
>>> public class ImageEntityProvider implements
>>> EntityProvider<IIOImage> {
>>> @ConsumeMime("application/xml,image/jpg,image/png,image/gif")
>>> public IIOImage readFrom(Class<IIOImage> type,
>>> MediaType mediaType,
>>> MultivaluedMap<String, String> httpHeaders,
>>> InputStream entityStream)
>>> throws IOException {...}
>>> @ProduceMime("image/jpg,image/png,image/gif")
>>> public void writeTo(IIOImage image,
>>> MediaType mediaTypes,
>>> MultivaluedMap<String, Object> httpHeaders,
>>> OutputStream entityStream)
>>> throws IOException {...}
>>>
>> Move the ConsumeMime and ProduceMime to the class as you show
>> below, you also need to add the supports method. The supports
>> method allows an entity provider to support entities based on
>> criteria other than the class of the entity. E.g. the JAXB provider
>> is declared as "implements EntityProvider<Object>" but only
>> supports classes annotated with @XmlRootElement.
>>
>>> The spec also mentions the use of the @Contract annotation, but
>>> I'm not clear on the proper usage or the specific functionality
>>> it provides. In regards to the @ProduceMime and @ConsumeMime
>>> annotations, is it also possible to be able to annotate the
>>> provider this way?
>>>
>>> @Provider
>>> @ProduceMime("image/jpg,image/png,image/gif")
>>> @ConsumeMime("application/xml,image/jpg,image/png,image/gif")
>>> public class ImageEntityProvider implements
>>> EntityProvider<IIOImage> {
>>>
>>> public IIOImage readFrom(Class<IIOImage> type,
>>> MediaType mediaType,
>>> MultivaluedMap<String, String> httpHeaders,
>>> InputStream entityStream)
>>> throws IOException {...}
>>>
>>> public void writeTo(IIOImage image,
>>> MediaType mediaTypes,
>>> MultivaluedMap<String, Object> httpHeaders,
>>> OutputStream entityStream)
>>> throws IOException {...}
>>>
>>>
>>> I'm just trying to clarify how this all should work in practice as
>>> it seems a bit vague at the moment. Is this syntax correct?
>>>
>> Exactly. Support for @Provider isn't yet implemented in Jersey
>> which instead uses files in jersey/src/impl/META-INF/services to
>> discover providers. The plan is that the JSR 311 runtime will scan
>> for classes annotated with @Contract and @Provider to remove the
>> need for such static configuration files. @Contract identifies an
>> interface/abstract class for which providers are expected (e.g.
>> EntityProvider), this corresponds to the name of the files
>> currently in jersey/src/impl/META-INF/services. @Provider
>> identifies classes that implement one or more interfaces/abstract
>> classes annotated with @Contract and this corresponds to an entry
>> in one of the files in jersey/src/impl/META-INF/services.
>>
>> Hope that makes it a little clearer.
>>
>> Marc.
>>
>>
>> ---
>> Marc Hadley <marc.hadley at sun.com>
>> CTO Office, Sun Microsystems.
>>
>>
>> ---------------------------------------------------------------------
>> To
>
---
Marc Hadley <marc.hadley at sun.com>
CTO Office, Sun Microsystems.