Re: JSR311: ProviderFactory API needs a bit refactoring?

From: Marc Hadley <Marc.Hadley_at_Sun.COM>
Date: Wed, 07 Nov 2007 11:14:49 -0500

On Nov 7, 2007, at 6:39 AM, Paul Sandoz wrote:
>> Split them into two interfaces. We may as well take stefans comment
>> into consideration and rename the EntityProvider to something less
>> confusing.
> Agreed, what about MessageBodyReader and MessageBodyWriter ? I like
> the idea of keeping the names close to reading/writing since that is
> what these do with InputStream and OutputStream respectively.
> While we are this the topic... It is sometimes useful for a
> container to ask a writer if it knows the size of something it will
> write, so the container can use chunked encoding or Content-Length,
> for example if File or byte[], or ByteArrayInputStream types are
> used then a writer knows the length. So we could have a method:
> // Returns a non-negative integer if size is known
> long MessageBodyWriter.getSize(T t)
Something like:

public interface MessageBodyReader<T> {
     boolean isReadable(Class<?> type);
     T readFrom(Class<T> type, MediaType mediaType,
             MultivaluedMap<String, String> httpHeaders,
             InputStream entityStream) throws IOException;


public interface MessageBodyWriter<T> {
     boolean isWriteable(Class<?> type);
     void writeTo(T t, MediaType mediaType,
             MultivaluedMap<String, Object> httpHeaders,
             OutputStream entityStream) throws IOException;
     long getSize(T t)

with the corresponding:

public abstract class ProviderFactory {
     public abstract <T> MessageBodyReader<T>
createMessageBodyReader(Class<T> type, MediaType media);
     public abstract <T> MessageBodyWriter<T>
createMessageBodyWriter(Class<T> type, MediaType media);


Marc Hadley <marc.hadley at>
CTO Office, Sun Microsystems.