How to use

getField

method

in

java.lang.Class

protected ResolvableType getGenericApplicationEventType(String fieldName) {
  try {
    return ResolvableType.forField(TestEvents.class.getField(fieldName));
  }
  catch (NoSuchFieldException ex) {
    throw new IllegalStateException("No such field on Events '" + fieldName + "'");
  }
}

@Test
public void isAssignableMapKeyValueTypes() throws Exception {
  assertTrue(new TypeDescriptor(getClass().getField("mapField")).isAssignableTo(new TypeDescriptor(getClass().getField("mapField"))));
  assertTrue(new TypeDescriptor(getClass().getField("notGenericMap")).isAssignableTo(new TypeDescriptor(getClass().getField("mapField"))));
  assertTrue(new TypeDescriptor(getClass().getField("mapField")).isAssignableTo(new TypeDescriptor(getClass().getField("notGenericMap"))));
  assertFalse(new TypeDescriptor(getClass().getField("isAssignableMapKeyValueTypes")).isAssignableTo(new TypeDescriptor(getClass().getField("mapField"))));
  assertTrue(TypeDescriptor.valueOf(Map.class).isAssignableTo(new TypeDescriptor(getClass().getField("mapField"))));
}

public void testInnerClassWithParameterizedOwner() throws Exception {
 Type fieldType = ParameterizedOuter.class.getField("field").getGenericType();
 assertEquals(
   fieldType, TypeToken.of(ParameterizedOuter.class).resolveType(fieldType).getType());
}

@Test
public void convertMapToMap() throws Exception {
  Map<String, String> foo = new HashMap<>();
  foo.put("1", "BAR");
  foo.put("2", "BAZ");
  @SuppressWarnings("unchecked")
  Map<Integer, FooEnum> map = (Map<Integer, FooEnum>) conversionService.convert(foo,
      TypeDescriptor.forObject(foo), new TypeDescriptor(getClass().getField("genericMap")));
  assertEquals(FooEnum.BAR, map.get(1));
  assertEquals(FooEnum.BAZ, map.get(2));
}

@Test
public void wildcardType() throws Exception {
  ParameterizedType typeSource = (ParameterizedType) SerializableTypeWrapper.forField(Fields.class.getField("wildcardType"));
  WildcardType type = (WildcardType) typeSource.getActualTypeArguments()[0];
  assertThat(type.toString(), equalTo("? extends java.lang.CharSequence"));
  assertSerializable(type);
  assertSerializable(type.getLowerBounds());
  assertSerializable(type.getUpperBounds());
}

@Test
public void testWildcardMap() throws Exception {
  Map<String, String> input = new LinkedHashMap<>();
  input.put("key", "value");
  Object converted = conversionService.convert(input, TypeDescriptor.forObject(input), new TypeDescriptor(getClass().getField("wildcardMap")));
  assertEquals(input, converted);
}

@Test
public void arrayClassType() throws Exception {
  ResolvableType type = ResolvableType.forField(Fields.class.getField("arrayClassType"));
  assertThat(type.getType(), instanceOf(Class.class));
  assertThat(((Class) type.getType()).isArray(), equalTo(true));
}

@Test
public void testStringToEnumSet() throws Exception {
  assertEquals(EnumSet.of(Foo.BAR), conversionService.convert("BAR", TypeDescriptor.valueOf(String.class),
      new TypeDescriptor(getClass().getField("enumSet"))));
}

@Test
public void resolveArrayClassType() throws Exception {
  ResolvableType type = ResolvableType.forField(Fields.class.getField("arrayClassType"));
  assertThat(type.resolve(), equalTo((Class) List[].class));
}

@Test
public void paramaterizedType() throws Exception {
  ResolvableType type = ResolvableType.forField(Fields.class.getField("parameterizedType"));
  assertThat(type.getType(), instanceOf(ParameterizedType.class));
}

@Test
public void resolveWildcardLowerBounds() throws Exception {
  ResolvableType type = ResolvableType.forField(Fields.class.getField("wildcardSuperType"));
  assertThat(type.getGeneric().resolve(), equalTo((Class) Number.class));
}

@Test
public void getGenericOfGenericByIndexes() throws Exception {
  ResolvableType type = ResolvableType.forField(Fields.class.getField("stringListList"));
  assertThat(type.getGeneric(0, 0).getType(), equalTo((Type) String.class));
}

@Test
public void emptyMapDifferentTargetImplType() throws Exception {
  Map<String, String> map = new HashMap<>();
  TypeDescriptor sourceType = TypeDescriptor.forObject(map);
  TypeDescriptor targetType = new TypeDescriptor(getClass().getField("emptyMapDifferentTarget"));
  assertTrue(conversionService.canConvert(sourceType, targetType));
  @SuppressWarnings("unchecked")
  LinkedHashMap<String, String> result = (LinkedHashMap<String, String>) conversionService.convert(map, sourceType, targetType);
  assertEquals(map, result);
  assertEquals(LinkedHashMap.class, result.getClass());
}

@Test
public void wildcardType() throws Exception {
  ResolvableType type = ResolvableType.forField(Fields.class.getField("wildcardType"));
  assertThat(type.getType(), instanceOf(ParameterizedType.class));
  assertThat(type.getGeneric().getType(), instanceOf(WildcardType.class));
}

@Test
public void getGenericByIndex() throws Exception {
  ResolvableType type = ResolvableType.forField(Fields.class.getField("stringIntegerMultiValueMap"));
  assertThat(type.getGeneric(0).getType(), equalTo((Type) String.class));
  assertThat(type.getGeneric(1).getType(), equalTo((Type) Integer.class));
}

@Test
public void serialize() throws Exception {
  testSerialization(ResolvableType.forClass(List.class));
  testSerialization(ResolvableType.forField(Fields.class.getField("charSequenceList")));
  testSerialization(ResolvableType.forMethodParameter(Methods.class.getMethod("charSequenceParameter", List.class), 0));
  testSerialization(ResolvableType.forMethodReturnType(Methods.class.getMethod("charSequenceReturn")));
  testSerialization(ResolvableType.forConstructorParameter(Constructors.class.getConstructor(List.class), 0));
  testSerialization(ResolvableType.forField(Fields.class.getField("charSequenceList")).getGeneric());
  ResolvableType deserializedNone = testSerialization(ResolvableType.NONE);
  assertThat(deserializedNone, sameInstance(ResolvableType.NONE));
}

@Test
public void elementTypePreserveContext() throws Exception {
  TypeDescriptor desc = new TypeDescriptor(getClass().getField("listPreserveContext"));
  assertEquals(Integer.class, desc.getElementTypeDescriptor().getElementTypeDescriptor().getType());
  List<Integer> value = new ArrayList<>(3);
  desc = desc.elementTypeDescriptor(value);
  assertEquals(Integer.class, desc.getElementTypeDescriptor().getType());
  assertNotNull(desc.getAnnotation(FieldAnnotation.class));
}

@Test
public void testSpr11219() throws Exception {
  ResolvableType type = ResolvableType.forField(BaseProvider.class.getField("stuff"), BaseProvider.class);
  assertTrue(type.getNested(2).isAssignableFrom(ResolvableType.forClass(BaseImplementation.class)));
  assertEquals("java.util.Collection<org.springframework.core.ResolvableTypeTests$IBase<?>>", type.toString());
}

@Test
public void fieldScalar() throws Exception {
  TypeDescriptor typeDescriptor = new TypeDescriptor(getClass().getField("fieldScalar"));
  assertFalse(typeDescriptor.isPrimitive());
  assertFalse(typeDescriptor.isArray());
  assertFalse(typeDescriptor.isCollection());
  assertFalse(typeDescriptor.isMap());
  assertEquals(Integer.class, typeDescriptor.getType());
  assertEquals(Integer.class, typeDescriptor.getObjectType());
}

@Test
public void fieldMap() throws Exception {
  TypeDescriptor desc = new TypeDescriptor(TypeDescriptorTests.class.getField("fieldMap"));
  assertTrue(desc.isMap());
  assertEquals(Integer.class, desc.getMapKeyTypeDescriptor().getElementTypeDescriptor().getType());
  assertEquals(Long.class, desc.getMapValueTypeDescriptor().getElementTypeDescriptor().getType());
}