javax.ws.rs.ext.MessageBodyWriter Maven / Gradle / Ivy
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package javax.ws.rs.ext;
import java.io.OutputStream;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.MultivaluedMap;
/**
* Contract for a provider that supports the conversion of a Java type to a
* stream.
*
* A {@code MessageBodyWriter} implementation may be annotated
* with {@link javax.ws.rs.Produces} to restrict the media types for which it will
* be considered suitable.
*
* Providers implementing {@code MessageBodyWriter} contract must be either programmatically
* registered in a JAX-RS runtime or must be annotated with
* {@link javax.ws.rs.ext.Provider @Provider} annotation to be automatically discovered
* by the JAX-RS runtime during a provider scanning phase.
*
*
* @param the type that can be written.
* @author Paul Sandoz
* @author Marc Hadley
* @see Provider
* @see javax.ws.rs.Produces
* @since 1.0
*/
public interface MessageBodyWriter {
/**
* Ascertain if the MessageBodyWriter supports a particular type.
*
* @param type the class of instance that is to be written.
* @param 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. {@link javax.ws.rs.core.GenericEntity}
* provides a way to specify this information at runtime.
* @param annotations an array of the annotations attached to the message entity instance.
* @param mediaType the media type of the HTTP entity.
* @return {@code true} if the type is supported, otherwise {@code false}.
*/
public boolean isWriteable(Class type, Type genericType,
Annotation[] annotations, MediaType mediaType);
/**
* Originally, the method has been called before {@code writeTo} to ascertain the length in bytes of
* the serialized form of {@code t}. A non-negative return value has been used in a HTTP
* {@code 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 {@code MessageBodyWriter} implementations are advised to return {@code -1}
* from the method. Responsibility to compute the actual {@code Content-Length} header value has been
* delegated to JAX-RS runtime.
*
*
* @param t the instance to write
* @param type the class of instance that is to be written.
* @param genericType the type of instance to be written. {@link javax.ws.rs.core.GenericEntity}
* provides a way to specify this information at runtime.
* @param annotations an array of the annotations attached to the message entity instance.
* @param mediaType the media type of the HTTP entity.
* @return length in bytes or -1 if the length cannot be determined in advance.
*/
public default long getSize(T t, Class type, Type genericType, Annotation[] annotations,
MediaType mediaType) {
return -1L;
}
/**
* 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.
*
* @param t the instance to write.
* @param type the class of instance that is to be written.
* @param genericType the type of instance to be written. {@link javax.ws.rs.core.GenericEntity}
* provides a way to specify this information at runtime.
* @param annotations an array of the annotations attached to the message entity instance.
* @param mediaType the media type of the HTTP entity.
* @param httpHeaders a mutable map of the HTTP message headers.
* @param entityStream the {@link OutputStream} for the HTTP entity. The
* implementation should not close the output stream.
* @throws java.io.IOException if an IO error arises.
* @throws javax.ws.rs.WebApplicationException
* if a specific HTTP error response needs to be produced.
* Only effective if thrown prior to the message being committed.
*/
public void writeTo(T t, Class type, Type genericType, Annotation[] annotations,
MediaType mediaType,
MultivaluedMap httpHeaders,
OutputStream entityStream)
throws java.io.IOException, javax.ws.rs.WebApplicationException;
}