Interface MessageBodyReader<T>
- Type Parameters:
T
- Java type supported by the provider
MessageBodyReader
implementation may be annotated
with Consumes
to restrict the media types for which it will
be considered suitable.
Providers implementing MessageBodyReader
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.
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Method Summary
Modifier and TypeMethodDescriptionboolean
isReadable
(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) Ascertain if the MessageBodyReader can produce an instance of a particular type.readFrom
(Class<T> type, Type genericType, Annotation[] annotations, MediaType mediaType, MultivaluedMap<String, String> httpHeaders, InputStream entityStream) Read a type from theInputStream
.
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Method Details
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isReadable
Ascertain if the MessageBodyReader can produce an instance of a particular type. Thetype
parameter gives the class of the instance that should be produced, thegenericType
parameter gives thejava.lang.reflect.Type
of the instance that should be produced. E.g. if the instance to be produced isList<String>
, thetype
parameter will bejava.util.List
and thegenericType
parameter will bejava.lang.reflect.ParameterizedType
.- Parameters:
type
- the class of instance to be produced.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 byMethod.getGenericParameterTypes
.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 byMethod.getParameterAnnotations
.mediaType
- the media type of the HTTP entity, if one is not specified in the request thenapplication/octet-stream
is used.- Returns:
true
if the type is supported, otherwisefalse
.
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readFrom
T readFrom(Class<T> type, Type genericType, Annotation[] annotations, MediaType mediaType, MultivaluedMap<String, String> httpHeaders, InputStream entityStream) throws IOException, WebApplicationExceptionRead a type from theInputStream
.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
NoContentException
in case no zero-length entity representation is defined for the supported Java type. ANoContentException
, if thrown by a message body reader while reading a server request entity, is automatically translated by JAX-RS server runtime into aBadRequestException
wrapping the originalNoContentException
and rethrown for a standard processing by the registeredexception mappers
.- Parameters:
type
- the type that is to be read from the entity stream.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 byMethod.getGenericParameterTypes
.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 byMethod.getParameterAnnotations
.mediaType
- the media type of the HTTP entity.httpHeaders
- the read-only HTTP headers associated with HTTP entity.entityStream
- theInputStream
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.- Returns:
- 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
NoContentException
in case no zero-length entity representation is defined for the supported Java type. - Throws:
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,NoContentException
is expected to be thrown.WebApplicationException
- if a specific HTTP error response needs to be produced. Only effective if thrown prior to the response being committed.
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