code: public boolean isReadable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
  		if (!hasMatchingMediaType(mediaType)) {
  			return false;
  		}
  
  		return isValidType(type, annotations);
  	}
docs: Method that JAX-RS container calls to try to check whether values of
  given type (and media type) can be deserialized by this provider.