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 ProduceMime to restrict the media types for which it will be considered suitable.

See Also:

Provider, ProduceMime

Method Summary

long	getSize(T t) 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) 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)

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. E.g. if the message body is to be produced from a field, this will be the declared type of the field as returned by Field.getGenericType.

annotations - an array of the annotations on the declaration of the artifact that will be written. E.g. if the message body is to be produced from a field, this will be the annotations on that field returned by Field.getDeclaredAnnotations.

Returns:

true if the type is supported, otherwise false.

getSize

long getSize(T t)

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 type

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. E.g. if the message body is to be produced from a field, this will be the declared type of the field as returned by Field.getGenericType.

annotations - an array of the annotations on the declaration of the artifact that will be written. E.g. if the message body is to be produced from a field, this will be the annotations on that field returned by Field.getDeclaredAnnotations.

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 input 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.