public static void initMapper(TypeSpec.Builder builder, String name, VavrModule.Settings settings) {
    Modifier[] mods = new Modifier[] { Modifier.PRIVATE, Modifier.STATIC, Modifier.FINAL };
    if (settings != null) {
        builder.addField(FieldSpec.builder(ClassName.get(VavrModule.Settings.class), name + "_SETTINGS", mods)
                .initializer("new $T()\n        .useOptionInPlainFormat($L).deserializeNullAsEmptyCollection($L)",
                        ClassName.get(VavrModule.Settings.class),
                        settings.useOptionInPlainFormat(), settings.deserializeNullAsEmptyCollection())
                .build());
        builder.addField(FieldSpec.builder(ClassName.get(VavrModule.class), name + "_MODULE", mods)
                .initializer("new $T($L)", ClassName.get(VavrModule.class), name + "_SETTINGS")
                .build());
    } else {
        builder.addField(FieldSpec.builder(ClassName.get(VavrModule.class), name + "_MODULE", mods)
                .initializer("new $T()", ClassName.get(VavrModule.class))
                .build());
    }
    builder.addField(FieldSpec.builder(ClassName.get(ObjectMapper.class), name, mods)
            .initializer("new $T().registerModule($L)", ClassName.get(ObjectMapper.class), name + "_MODULE")
            .build());
}
 

@Test
public void itShouldSerializeVavrOptionYearMonthAsStringWithoutJsonFormat() throws IOException {
    // Given an instance with io.vavr.control.Option
    MyVavrOptionalClassWithoutFormat obj = new MyVavrOptionalClassWithoutFormat();
    obj.operatingMonth = Option.of(YearMonth.of(2019, 12));

    // When serializing the instance using object mapper
    // with Java Time Module and VAVR Module
    ObjectMapper objectMapper = mapper();
    objectMapper.registerModule(new JavaTimeModule());
    objectMapper.registerModule(new VavrModule());
    String json = objectMapper.writeValueAsString(obj);

    // Then serialization is successful
    Assertions.assertEquals("{\"operatingMonth\":[2019,12]}", json);
    MyVavrOptionalClassWithoutFormat obj2 = objectMapper.readValue(json, MyVavrOptionalClassWithoutFormat.class);

    // And deserialization is successful
    Assertions.assertEquals(Option.of(YearMonth.of(2019, 12)), obj2.operatingMonth);
}
 

@Test
public void itShouldSerializeVavrOptionYearMonthAsString() throws IOException {
    // Given an instance with io.vavr.control.Option
    MyVavrOptionClassWithFormat obj = new MyVavrOptionClassWithFormat();
    obj.operatingMonth = Option.of(YearMonth.of(2019, 12));

    // When serializing the instance using object mapper
    // with Java Time Module and VAVR Module
    ObjectMapper objectMapper = mapper();
    objectMapper.registerModule(new JavaTimeModule());
    objectMapper.registerModule(new VavrModule());
    String json = objectMapper.writeValueAsString(obj);

    // Then serialization is failed
    Assertions.assertEquals("{\"operatingMonth\":\"12-2019\"}", json);
    MyVavrOptionClassWithFormat obj2 = objectMapper.readValue(json, MyVavrOptionClassWithFormat.class);

    // And deserialization is failed
    Assertions.assertEquals(Option.of(YearMonth.of(2019, 12)), obj2.operatingMonth);
}
 

@Test
void test4() throws IOException {
    VavrModule.Settings settings = new VavrModule.Settings();
    settings.deserializeNullAsEmptyCollection(true);
    ObjectMapper mapper = mapper(settings);
    Set<?> restored = mapper.readValue("null", typeReference());
    Assertions.assertTrue(restored.isEmpty());
}
 

@Test
void test4() throws IOException {
    VavrModule.Settings settings = new VavrModule.Settings();
    settings.deserializeNullAsEmptyCollection(true);
    ObjectMapper mapper = mapper(settings);
    Seq<?> restored = (Seq<?>) mapper.readValue("null", clz());
    Assertions.assertTrue(restored.isEmpty());
}
 

public static <T> void json_roundtrip_test(T value, Class<T> valueType) throws IOException {
    ObjectMapper mapper = new ObjectMapper();
    mapper.registerModule(new VavrModule());
    String asString = mapper.writeValueAsString(value);
    assertNotNull(asString);
    final T value_decoded = mapper.readValue(asString, valueType);
    assertEquals(value, value_decoded);
}
 

@BeforeEach
public void before() {
    mapper = new ObjectMapper();
    SimpleModule module = new VavrModule()
            .addKeyDeserializer(MyComparable.class, new KeyDeserializer() {
                @Override
                public Object deserializeKey(String key, DeserializationContext ctxt) {
                    return new MyComparable(Integer.parseInt(key));
                }
            });
    mapper.registerModule(module);
}
 

@Test
void itShouldSerializeVavrListWithVavrModule() throws Exception {
    MyVavrClass myClass = new MyVavrClass();
    myClass.dates = List.of(new Date(1591221600000L), new Date(1591308000000L));

    ObjectMapper mapper = new ObjectMapper();
    mapper.registerModule(new VavrModule());

    String json = mapper.writeValueAsString(myClass);
    assertEquals("{\"dates\":[\"2020-06-04\",\"2020-06-05\"]}", json);
}
 

@Test
void itShouldSerializeVavrListWithVavrModuleAndJavaTimeModule() throws Exception {
    MyVavrClass myClass = new MyVavrClass();
    myClass.dates = List.of(new Date(1591221600000L), new Date(1591308000000L));

    ObjectMapper mapper = new ObjectMapper();
    mapper.registerModule(new VavrModule());
    mapper.registerModule(new JavaTimeModule());

    String json = mapper.writeValueAsString(myClass);
    assertEquals("{\"dates\":[\"2020-06-04\",\"2020-06-05\"]}", json);
}
 

public static Schema parseJson(Reader in) throws IOException {
    ObjectMapper mapper = new ObjectMapper();
    mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
    mapper.registerModule(new VavrModule());
    return mapper.readValue(in, Schema.class);
}
 

public VavrSerializers(VavrModule.Settings settings) {
    this.settings = settings;
}
 

public VavrDeserializers(VavrModule.Settings settings) {
    this.settings = settings;
}