/*
* Copyright (c) 2010, 2017 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0, which is available at
* http://www.eclipse.org/legal/epl-2.0.
*
* This Source Code may also be made available under the following Secondary
* Licenses when the conditions for such availability set forth in the
* Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
* version 2 with the GNU Classpath Exception, which is available at
* https://www.gnu.org/software/classpath/license.html.
*
* SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
*/
package javax.ws.rs.ext;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.MultivaluedMap;
import java.io.OutputStream;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;
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 an API runtime or must be annotated with @Provider annotation to be automatically discovered by the runtime during a provider scanning phase.
Author: Paul Sandoz, Marc Hadley Type parameters: - <T> – the type that can be written.
See Also: Since: 1.0
/**
* 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.
* <p>
* Providers implementing {@code MessageBodyWriter} contract must be either programmatically
* registered in an API runtime or must be annotated with
* {@link javax.ws.rs.ext.Provider @Provider} annotation to be automatically discovered
* by the runtime during a provider scanning phase.
* </p>
*
* @param <T> 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<T> {
Ascertain if the MessageBodyWriter supports a particular type.
Params: - 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, otherwise false.
/**
* 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 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 version 2.0 of this API, the method has been deprecated and the value returned by the method is ignored by an API 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 the runtime.
Params: - 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.
Returns: length in bytes or -1 if the length cannot be determined in advance.
/**
* 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.
* <p>
* As of version 2.0 of this API, the method has been deprecated and the value returned by the method is ignored
* by an API 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 the runtime.
* </p>
*
* @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.
Params: - 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 – the
OutputStream 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.
/**
* 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<String, Object> httpHeaders,
OutputStream entityStream)
throws java.io.IOException, javax.ws.rs.WebApplicationException;
}