jakarta.ws.rs.ext.MessageBodyReader Maven / Gradle / Ivy
/*
* Copyright (c) 2010, 2019 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 jakarta.ws.rs.ext;
import java.io.InputStream;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;
import jakarta.ws.rs.core.MediaType;
import jakarta.ws.rs.core.MultivaluedMap;
/**
* Contract for a provider that supports the conversion of a stream to a Java type.
*
* A {@code MessageBodyReader} implementation may be annotated with {@link jakarta.ws.rs.Consumes} to restrict the media
* types for which it will be considered suitable. The {@code MessageBodyReader} pipeline is executed if the matching
* resource method declares an entity parameter or uses at least one {@link jakarta.ws.rs.FormParam}.
*
* Providers implementing {@code MessageBodyReader} contract must be either programmatically registered in a JAX-RS
* runtime or must be annotated with {@link jakarta.ws.rs.ext.Provider @Provider} annotation to be automatically
* discovered by the JAX-RS runtime during a provider scanning phase.
*
*
* @param Java type supported by the provider
* @author Paul Sandoz
* @author Marc Hadley
* @see Provider
* @see jakarta.ws.rs.Consumes
* @since 1.0
*/
public interface MessageBodyReader {
/**
* Ascertain if the MessageBodyReader can produce an instance of a particular type. The {@code type} parameter gives the
* class of the instance that should be produced, the {@code genericType} parameter gives the
* {@link java.lang.reflect.Type java.lang.reflect.Type} of the instance that should be produced. E.g. if the instance
* to be produced is {@code List}, the {@code type} parameter will be {@code java.util.List} and the
* {@code genericType} parameter will be {@link java.lang.reflect.ParameterizedType
* java.lang.reflect.ParameterizedType}.
*
* @param type the class of instance to be produced.
* @param genericType the type of instance to be produced. E.g. if the message body is to be converted into a method
* parameter, this will be the formal type of the method parameter as returned by
* {@code Method.getGenericParameterTypes}.
* @param annotations an array of the annotations on the declaration of the artifact that will be initialized with the
* produced instance. E.g. if the message body is to be converted into a method parameter, this will be the annotations
* on that parameter returned by {@code Method.getParameterAnnotations}.
* @param mediaType the media type of the HTTP entity, if one is not specified in the request then
* {@code application/octet-stream} is used.
* @return {@code true} if the type is supported, otherwise {@code false}.
*/
public boolean isReadable(Class type, Type genericType,
Annotation[] annotations, MediaType mediaType);
/**
* Read a type from the {@link InputStream}.
*
* In case the entity input stream is empty, the reader is expected to either return a Java representation of a
* zero-length entity or throw a {@link jakarta.ws.rs.core.NoContentException} in case no zero-length entity
* representation is defined for the supported Java type. A {@code NoContentException}, if thrown by a message body
* reader while reading a server request entity, is automatically translated by JAX-RS server runtime into a
* {@link jakarta.ws.rs.BadRequestException} wrapping the original {@code NoContentException} and rethrown for a standard
* processing by the registered {@link jakarta.ws.rs.ext.ExceptionMapper exception mappers}.
*
*
* @param type the type that is to be read from the entity stream.
* @param genericType the type of instance to be produced. E.g. if the message body is to be converted into a method
* parameter, this will be the formal type of the method parameter as returned by
* {@code Method.getGenericParameterTypes}.
* @param annotations an array of the annotations on the declaration of the artifact that will be initialized with the
* produced instance. E.g. if the message body is to be converted into a method parameter, this will be the annotations
* on that parameter returned by {@code Method.getParameterAnnotations}.
* @param mediaType the media type of the HTTP entity.
* @param httpHeaders the read-only HTTP headers associated with HTTP entity.
* @param entityStream the {@link InputStream} of the HTTP entity. The caller is responsible for ensuring that the input
* stream ends when the entity has been consumed. The implementation should not close the input stream.
* @return the type that was read from the stream. In case the entity input stream is empty, the reader is expected to
* either return an instance representing a zero-length entity or throw a {@link jakarta.ws.rs.core.NoContentException} in
* case no zero-length entity representation is defined for the supported Java type.
* @throws java.io.IOException if an IO error arises. In case the entity input stream is empty and the reader is not
* able to produce a Java representation for a zero-length entity, {@code NoContentException} is expected to be thrown.
* @throws jakarta.ws.rs.WebApplicationException if a specific HTTP error response needs to be produced. Only effective if
* thrown prior to the response being committed.
*/
public T readFrom(Class type, Type genericType,
Annotation[] annotations, MediaType mediaType,
MultivaluedMap httpHeaders,
InputStream entityStream) throws java.io.IOException, jakarta.ws.rs.WebApplicationException;
}