Possible to add a `getFields` instance method?

[bricejlin]

Any thoughts on introducing a getFields method to automatter objects? Would love to be able to iterate through an Automatter Object's fields. I have a usecase to check that at least one field is populated in the object and right now, I'm forced to manually check every field to get that.

[danielnorberg]

That sounds useful. Feel free to submit a PR =)

Meanwhile, here's an example of some utility methods for doing this using reflection.

public static void main(String... args) {
  Foobar foobar = new FoobarBuilder()
      .foo("hello world")
      .bar(17)
      .build();

  boolean anyPopulated = anyFieldPopulated(Foobar.class, foobar);

  System.out.println(anyPopulated);
}

static <T> boolean anyFieldPopulated(Class<T> cls, T o) {
  return getFields(cls)
      .map(field -> getValue(field, o))
      .filter(Objects::nonNull)
      // TODO: handle collections?
      .anyMatch(value -> value.getClass() != Optional.class ||
          ((Optional<?>) value).isPresent());
}

static Stream<Method> getFields(Class<?> cls) {
  return Stream.of(cls.getMethods())
      .filter(m -> m.getDeclaringClass() == cls)
      .filter(m -> !m.getReturnType().getName().endsWith("Builder"));
}

static Object getValue(Method m, Object o) {
  try {
    return m.invoke(o);
  } catch (IllegalAccessException | InvocationTargetException e) {
    throw new RuntimeException(e);
  }
}