Top Description Methods
javax.ws.rs.ext

public Interface MessageBodyWriter<T>

Type Parameters
<T>
the type that can be written.
Imports
java.io.OutputStream, java.lang.annotation.Annotation, java.lang.reflect.Type, javax.ws.rs.core.MediaType, .MultivaluedMap
Contract for a provider that supports the conversion of a Java type to a stream. A MessageBodyWriter implementation may be annotated with javax.ws.rs.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.

Authors
Paul Sandoz, Marc Hadley
Since
1.0
See Also
Provider, javax.ws.rs.Produces

Method Summary

Modifier and TypeMethod and Description
public default long

Returns:

length in bytes or -1 if the length cannot be determined in advance.
getSize(T
the instance to write
t, Class<?>
the class of instance that is to be written.
type, Type
the type of instance to be written. javax.ws.rs.core.GenericEntity provides a way to specify this information at runtime.
genericType, Annotation[]
an array of the annotations attached to the message entity instance.
annotations, MediaType
the media type of the HTTP entity.
mediaType)

Originally, the method has been called before writeTo to ascertain the length in bytes of the serialized form of t.

public boolean

Returns:

true if the type is supported, otherwise false.
isWriteable(Class<?>
the class of instance that is to be written.
type, Type
the type of instance to be written, obtained either by reflection of a resource method return type or via inspection of the returned instance. javax.ws.rs.core.GenericEntity provides a way to specify this information at runtime.
genericType, Annotation[]
an array of the annotations attached to the message entity instance.
annotations, MediaType
the media type of the HTTP entity.
mediaType)

Ascertain if the MessageBodyWriter supports a particular type.

public void
writeTo(T
the instance to write.
t, Class<?>
the class of instance that is to be written.
type, Type
the type of instance to be written. javax.ws.rs.core.GenericEntity provides a way to specify this information at runtime.
genericType, Annotation[]
an array of the annotations attached to the message entity instance.
annotations, MediaType
the media type of the HTTP entity.
mediaType, MultivaluedMap<String, Object>
a mutable map of the HTTP message headers.
httpHeaders, OutputStream
the OutputStream for the HTTP entity. The implementation should not close the output stream.
entityStream)

Write a type to an HTTP message.

Method Detail

getSizeback to summary
public default long getSize(T t, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType)

Originally, the method has been called before writeTo to ascertain the length in bytes of the serialized form of t. A non-negative return value has been used in a HTTP Content-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 actual Content-Length header value has been delegated to JAX-RS runtime.

Parameters
t:T

the instance to write

type:Class<?>

the class of instance that is to be written.

genericType:Type

the type of instance to be written. javax.ws.rs.core.GenericEntity provides a way to specify this information at runtime.

annotations:Annotation[]

an array of the annotations attached to the message entity instance.

mediaType:MediaType

the media type of the HTTP entity.

Returns:long

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

isWriteableback to summary
public boolean isWriteable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType)

Ascertain if the MessageBodyWriter supports a particular type.

Parameters
type:Class<?>

the class of instance that is to be written.

genericType:Type

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

annotations:Annotation[]

an array of the annotations attached to the message entity instance.

mediaType:MediaType

the media type of the HTTP entity.

Returns:boolean

true if the type is supported, otherwise false.

writeToback to summary
public void writeTo(T t, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType, MultivaluedMap<String, Object> httpHeaders, OutputStream entityStream) throws IOException, WebApplicationException

Write 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:T

the instance to write.

type:Class<?>

the class of instance that is to be written.

genericType:Type

the type of instance to be written. javax.ws.rs.core.GenericEntity provides a way to specify this information at runtime.

annotations:Annotation[]

an array of the annotations attached to the message entity instance.

mediaType:MediaType

the media type of the HTTP entity.

httpHeaders:MultivaluedMap<String, Object>

a mutable map of the HTTP message headers.

entityStream:OutputStream

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

Exceptions
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.