methanol-jackson

Adapters for Jackson.

Installation

Gradle

implementation("com.github.mizosoft.methanol:methanol-jackson:1.7.0")

Maven

<dependency>
  <groupId>com.github.mizosoft.methanol</groupId>
   <artifactId>methanol-jackson</artifactId>
   <version>1.7.0</version>
</dependency>

Usage

var mapper = new JsonMapper();
var adapterCodec =
    AdapterCodec.newBuilder()
        .encoder(JacksonAdapterFactory.createJsonEncoder(mapper))
        .decoder(JacksonAdapterFactory.createJsonDecoder(mapper))
        .build();
var client =
    Methanol.newBuilder()
        .adapterCodec(adapterCodec)
        .build();

record Person(String name) {}

var bruceLee = new Person("Bruce Lee");
var response = client.send(
    MutableRequest.POST(".../echo", bruceLee, MediaType.APPLICATION_JSON),
    Person.class);
assertThat(response.body()).isEqualTo(bruceLee);

Formats

ObjectMapper implementations can be paired with one or more MediaTypes to create adapters for any format supported by Jackson. For instance, here's an adapter for XML that uses jackson-dataformat-xml.

 var mapper = new XmlMapper();
var adapterCodec =
    AdapterCodec.newBuilder()
        .encoder(
            JacksonAdapterFactory.createEncoder(
                mapper, MediaType.APPLICATION_XML, MediaType.TEXT_XML))
        .decoder(
            JacksonAdapterFactory.createDecoder(
                mapper, MediaType.APPLICATION_XML, MediaType.TEXT_XML))
        .build();

For binary formats, you usually can't just plug in an ObjectMapper as a schema must be applied for each type. Thus, you would use a custom ObjectReaderFactory and/or ObjectWriterFactory. Here's an adapter for Protocol Buffers. You'll need to know what types are expected beforehand.

record Point(int x, int y) {}

var schemas =
    Map.of(
        TypeRef.of(Point.class),
        ProtobufSchemaLoader.std.parse(
            """
                message Point {
                  required int32 x = 1;
                  required int32 y = 2;
                }
                """));
var mapper = new ProtobufMapper();
var adapterCodec =
    AdapterCodec.newBuilder()
        .encoder(
            JacksonAdapterFactory.createEncoder(
                mapper,
                (localMapper, typeRef) -> localMapper.writer(schemas.get(typeRef)),
                MediaType.APPLICATION_X_PROTOBUF))
        .decoder(
            JacksonAdapterFactory.createDecoder(
                mapper,
                (localMapper, typeRef) ->
                    mapper.readerFor(typeRef.rawType()).with(schemas.get(typeRef)),
                MediaType.APPLICATION_X_PROTOBUF));

Legacy Adapters

See Legacy Adapters