JAX-RS - MessageBodyReader Examples

@Provider
@Consumes({"application/yaml", MediaType.TEXT_PLAIN})
@Produces({"application/yaml", MediaType.TEXT_PLAIN})
public class YamlEntityProvider<T> implements MessageBodyWriter<T>, MessageBodyReader<T> {

    @Override
    public boolean isReadable(Class<?> type, Type genericType, Annotation[] annotations,
                              MediaType mediaType) {
        return true;
    }

    @Override
    public T readFrom(Class<T> type, Type genericType, Annotation[] annotations, MediaType mediaType,
                      MultivaluedMap<String, String> httpHeaders, InputStream entityStream)
            throws IOException, WebApplicationException {
        Yaml yaml = new Yaml();
        T t = yaml.loadAs(toString(entityStream), type);
        return t;
    }

    public static String toString(InputStream inputStream) {
        return new Scanner(inputStream, "UTF-8")
                .useDelimiter("\\A").next();
    }

    @Override
    public boolean isWriteable(Class<?> type, Type genericType, Annotation[] annotations,
                               MediaType mediaType) {
        return true;
    }

    @Override
    public long getSize(T t, Class<?> type, Type genericType, Annotation[] annotations,
                        MediaType mediaType) {
        return -1;
    }

    @Override
    public void writeTo(T t, Class<?> type, Type genericType, Annotation[] annotations,
                        MediaType mediaType, MultivaluedMap<String, Object> httpHeaders,
                        OutputStream entityStream) throws IOException, WebApplicationException {
        Yaml yaml = new Yaml();
        OutputStreamWriter writer = new OutputStreamWriter(entityStream);
        yaml.dump(t, writer);
        writer.close();
    }
}

@Provider
@Consumes({"application/yaml", MediaType.TEXT_PLAIN})
@Produces({"application/yaml", MediaType.TEXT_PLAIN})
public class YamlEntityProvider<T> implements MessageBodyWriter<T>, MessageBodyReader<T> {
    @Context
    private Providers providers;

    @Override
    public boolean isReadable(Class<?> type, Type genericType, Annotation[] annotations,
                              MediaType mediaType) {
        return true;
    }

    @Override
    public T readFrom(Class<T> type, Type genericType, Annotation[] annotations, MediaType mediaType,
                      MultivaluedMap<String, String> httpHeaders, InputStream entityStream)
            throws IOException, WebApplicationException {
        ContextResolver<YamlContext> cr = providers.getContextResolver(YamlContext.class, mediaType);
        YamlContext context = cr.getContext(type);
        T t = context.readEntity(entityStream, type);
        return t;
    }

    @Override
    public boolean isWriteable(Class<?> type, Type genericType, Annotation[] annotations,
                               MediaType mediaType) {
        return true;
    }

    @Override
    public long getSize(T t, Class<?> type, Type genericType, Annotation[] annotations,
                        MediaType mediaType) {
        return -1;
    }

    @Override
    public void writeTo(T t, Class<?> type, Type genericType, Annotation[] annotations,
                        MediaType mediaType, MultivaluedMap<String, Object> httpHeaders,
                        OutputStream entityStream) throws IOException, WebApplicationException {
        ContextResolver<YamlContext> cr = providers.getContextResolver(YamlContext.class, mediaType);
        YamlContext context = cr.getContext(type);
        context.writeEntity(entityStream, t);

    }
}