public final class CompositeAttributes implements Attributes {
  private final Attributes first;
  private final Attributes second;

  private CompositeAttributes(Attributes first, Attributes second) {
    this.first = first;
    this.second = second;
  }

  public static Attributes of(Attributes first, Attributes second) {
    return new CompositeAttributes(first, second);
  }

  @Nullable
  @Override
  public <T> T get(AttributeKey<T> attributeKey) {
    T value = first.get(attributeKey);
    if (value != null) {
      return value;
    }
    return second.get(attributeKey);
  }

  @Override
  public void forEach(BiConsumer<? super AttributeKey<?>, ? super Object> biConsumer) {
    first.forEach(biConsumer);
    second.forEach(biConsumer);
  }

  @Override
  public int size() {
    return first.size() + second.size();
  }

  @Override
  public boolean isEmpty() {
    return first.isEmpty() && second.isEmpty();
  }

  @Override
  public Map<AttributeKey<?>, Object> asMap() {
    Map<AttributeKey<?>, Object> map = new HashMap<>();
    map.putAll(first.asMap());
    map.putAll(second.asMap());
    return map;
  }

  @Override
  public AttributesBuilder toBuilder() {
    return first.toBuilder().putAll(second);
  }
}