javax.ws.rs.ext.MessageBodyReader Maven / Gradle / Ivy
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package javax.ws.rs.ext;
import java.io.InputStream;
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 stream to a
* Java type.
*
* A {@code MessageBodyReader} implementation may be annotated
* with {@link javax.ws.rs.Consumes} to restrict the media types for which it will
* be considered suitable.
*
* Providers implementing {@code MessageBodyReader} 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 Java type supported by the provider
* @author Paul Sandoz
* @author Marc Hadley
* @see Provider
* @see javax.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 javax.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 javax.ws.rs.BadRequestException}
* wrapping the original {@code NoContentException} and rethrown for a standard processing by
* the registered {@link javax.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 javax.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 javax.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, javax.ws.rs.WebApplicationException;
}