JsonAdapterAnnotationTypeAdapterFactory.java 文件源码

@SuppressWarnings("unchecked") // Casts guarded by conditionals.
static TypeAdapter<?> getTypeAdapter(ConstructorConstructor constructorConstructor, Gson gson,
    TypeToken<?> fieldType, JsonAdapter annotation) {
  Class<?> value = annotation.value();
  if (TypeAdapter.class.isAssignableFrom(value)) {
        Class<TypeAdapter<?>> typeAdapter = (Class<TypeAdapter<?>>) value;
    return constructorConstructor.get(TypeToken.get(typeAdapter)).construct();
  }
  if (TypeAdapterFactory.class.isAssignableFrom(value)) {
        Class<TypeAdapterFactory> typeAdapterFactory = (Class<TypeAdapterFactory>) value;
    return constructorConstructor.get(TypeToken.get(typeAdapterFactory))
        .construct()
        .create(gson, fieldType);
  }

  throw new IllegalArgumentException(
      "@JsonAdapter value must be TypeAdapter or TypeAdapterFactory reference.");
}