Package javax.ws.rs.ext
Interface MessageBodyWriter<T>
- Type Parameters:
T
- the type that can be written.
public interface MessageBodyWriter<T>
Contract for a provider that supports the conversion of a Java type to a
stream.
A
MessageBodyWriter
implementation may be annotated
with Produces
to restrict the media types for which it will
be considered suitable.
Providers implementing MessageBodyWriter
contract must be either programmatically
registered in a JAX-RS runtime or must be annotated with
@Provider
annotation to be automatically discovered
by the JAX-RS runtime during a provider scanning phase.
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Method Summary
Modifier and TypeMethodDescriptionlong
Originally, the method has been called beforewriteTo
to ascertain the length in bytes of the serialized form oft
.boolean
isWriteable
(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) Ascertain if the MessageBodyWriter supports a particular type.void
writeTo
(T t, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType, MultivaluedMap<String, Object> httpHeaders, OutputStream entityStream) Write a type to an HTTP message.
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Method Details
-
isWriteable
Ascertain if the MessageBodyWriter supports a particular type.- Parameters:
type
- the class of instance that is to be written.genericType
- the type of instance 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 attached to the message entity instance.mediaType
- the media type of the HTTP entity.- Returns:
true
if the type is supported, otherwisefalse
.
-
getSize
Originally, the method has been called beforewriteTo
to ascertain the length in bytes of the serialized form oft
. A non-negative return value has been used in a HTTPContent-Length
header.As of JAX-RS 2.0, the method has been deprecated and the value returned by the method is ignored by a JAX-RS runtime. All
MessageBodyWriter
implementations are advised to return-1
from the method. Responsibility to compute the actualContent-Length
header value has been delegated to JAX-RS runtime.- Parameters:
t
- the instance to writetype
- the class of instance that is to be written.genericType
- the type of instance to be written.GenericEntity
provides a way to specify this information at runtime.annotations
- an array of the annotations attached to the message entity instance.mediaType
- the media type of the HTTP entity.- Returns:
- length in bytes or -1 if the length cannot be determined in advance.
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writeTo
void writeTo(T t, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType, MultivaluedMap<String, Object> httpHeaders, OutputStream entityStream) throws IOException, WebApplicationExceptionWrite a type to an HTTP message. The message 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 message body.- Parameters:
t
- the instance to write.type
- the class of instance that is to be written.genericType
- the type of instance to be written.GenericEntity
provides a way to specify this information at runtime.annotations
- an array of the annotations attached to the message entity instance.mediaType
- the media type of the HTTP entity.httpHeaders
- a mutable map of the HTTP message headers.entityStream
- theOutputStream
for the HTTP entity. The implementation should not close the output stream.- Throws:
IOException
- if an IO error arises.WebApplicationException
- if a specific HTTP error response needs to be produced. Only effective if thrown prior to the message being committed.
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