javax.ws.rs.ext
Interface MessageBodyReader<T>

public interface MessageBodyReader<T>

Contract for a provider that supports the conversion of a stream to a Java type. To add a MessageBodyReader implementation, annotate the implementation class with @Provider. A MessageBodyReader implementation may be annotated with Consumes to restrict the media types for which it will be considered suitable.

See Also:

Provider, Consumes

Method Summary

boolean	isReadable(java.lang.Class<?> type, java.lang.reflect.Type genericType, java.lang.annotation.Annotation[] annotations, MediaType mediaType) Ascertain if the MessageBodyReader can produce an instance of a particular type.
T	readFrom(java.lang.Class<T> type, java.lang.reflect.Type genericType, java.lang.annotation.Annotation[] annotations, MediaType mediaType, MultivaluedMap<java.lang.String,java.lang.String> httpHeaders, java.io.InputStream entityStream) Read a type from the InputStream.

Method Detail

isReadable

boolean isReadable(java.lang.Class<?> type,
                   java.lang.reflect.Type genericType,
                   java.lang.annotation.Annotation[] annotations,
                   MediaType mediaType)

Ascertain if the MessageBodyReader can produce an instance of a particular type. The type parameter gives the class of the object that should be produced, the genericType parameter gives the java.lang.reflect.Type of the object that should be produced. E.g. if the object to be produced is List, the type parameter will be java.util.List and the genericType parameter will be java.lang.reflect.ParameterizedType.

Parameters:

type - the class of object to be produced.

genericType - the type of object 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 Method.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 by Method.getParameterAnnotations.

mediaType - the media type of the HTTP entity, if one is not specified in the request then application/octet-stream is used.

Returns:

true if the type is supported, otherwise false.

readFrom

T readFrom(java.lang.Class<T> type,
           java.lang.reflect.Type genericType,
           java.lang.annotation.Annotation[] annotations,
           MediaType mediaType,
           MultivaluedMap<java.lang.String,java.lang.String> httpHeaders,
           java.io.InputStream entityStream)
           throws java.io.IOException,
                  WebApplicationException

Read a type from the InputStream.

Parameters:

type - the type that is to be read from the entity stream.

genericType - the type of object 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 Method.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 by Method.getParameterAnnotations.

mediaType - the media type of the HTTP entity.

httpHeaders - the read-only HTTP headers associated with HTTP entity.

entityStream - the 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.

Returns:

the type that was read from the stream.

Throws:

java.io.IOException - if an IO error arises

WebApplicationException - if a specific HTTP error response needs to be produced. Only effective if thrown prior to the response being committed.