javax.ws.rs.ext
Interface MessageBodyWriter<T>

public interface MessageBodyWriter<T>

Contract for a provider that supports the conversion of a Java type to a stream. To add a MessageBodyWriter implementation, annotate the implementation class with @Provider. A MessageBodyWriter implementation may be annotated with Produces to restrict the media types for which it will be considered suitable.

See Also:

Provider, Produces

Method Summary

long	getSize(T t, java.lang.Class<?> type, java.lang.reflect.Type genericType, java.lang.annotation.Annotation[] annotations, MediaType mediaType) Called before writeTo to ascertain the length in bytes of the serialized form of t.
boolean	isWriteable(java.lang.Class<?> type, java.lang.reflect.Type genericType, java.lang.annotation.Annotation[] annotations, MediaType mediaType) Ascertain if the MessageBodyWriter supports a particular type.
void	writeTo(T t, java.lang.Class<?> type, java.lang.reflect.Type genericType, java.lang.annotation.Annotation[] annotations, MediaType mediaType, MultivaluedMap<java.lang.String,java.lang.Object> httpHeaders, java.io.OutputStream entityStream) Write a type to an HTTP response.

Method Detail

isWriteable

boolean isWriteable(java.lang.Class<?> type,
                    java.lang.reflect.Type genericType,
                    java.lang.annotation.Annotation[] annotations,
                    MediaType mediaType)

Ascertain if the MessageBodyWriter supports a particular type.

Parameters:

type - the class of object that is to be written.

genericType - the type of object to be written, obtained either by reflection of a resource method return type or via inspection of the returned instance. GenericEntity provides a way to specify this information at runtime.

annotations - an array of the annotations on the resource method that returns the object.

mediaType - the media type of the HTTP entity.

Returns:

true if the type is supported, otherwise false.

getSize

long getSize(T t,
             java.lang.Class<?> type,
             java.lang.reflect.Type genericType,
             java.lang.annotation.Annotation[] annotations,
             MediaType mediaType)

Called before writeTo to ascertain the length in bytes of the serialized form of t. A non-negative return value is used in a HTTP Content-Length header.

Parameters:

t - the instance to write

type - the class of object that is to be written.

genericType - the type of object to be written, obtained either by reflection of a resource method return type or by inspection of the returned instance. GenericEntity provides a way to specify this information at runtime.

annotations - an array of the annotations on the resource method that returns the object.

mediaType - the media type of the HTTP entity.

Returns:

length in bytes or -1 if the length cannot be determined in advance

writeTo

void writeTo(T t,
             java.lang.Class<?> type,
             java.lang.reflect.Type genericType,
             java.lang.annotation.Annotation[] annotations,
             MediaType mediaType,
             MultivaluedMap<java.lang.String,java.lang.Object> httpHeaders,
             java.io.OutputStream entityStream)
             throws java.io.IOException,
                    WebApplicationException

Write a type to an HTTP response. The response header map is mutable but any changes must be made before writing to the output stream since the headers will be flushed prior to writing the response body.

Parameters:

t - the instance to write.

type - the class of object that is to be written.

genericType - the type of object to be written, obtained either by reflection of a resource method return type or by inspection of the returned instance. GenericEntity provides a way to specify this information at runtime.

annotations - an array of the annotations on the resource method that returns the object.

mediaType - the media type of the HTTP entity.

httpHeaders - a mutable map of the HTTP response headers.

entityStream - the OutputStream for the HTTP entity. The implementation should not close the output stream.

Throws:

java.io.IOException - if an IO error arises

WebApplicationException - if a specific HTTP error response needs to be produced. Only effective if thrown prior to the response being committed.