인프런 커뮤니티 질문&답변

안녕하십니까 집합 함수 적용에 관해 궁금한 점이 있어서 질문 드립니다.

아래와 같이 AttributeConverter 적용 필드의 경우에는 QueryDSL로 집합함수 적용이 가능한 방법이 있는지 궁금합니다.

 

public class Product {
	public enum ProductStatus { PROCEEDING, SOLD_OUT;}

	@Id
	@GeneratedValue(strategy = GenerationType.IDENTITY)
	@Column(name = "PRODUCT_ID")
	private Long id;

	@Column(name = "TITLE")
	private String title;

	@Column(name = "PRICE")
	private Money price;
}

public class Money {
	public static final Money ZERO = Money.wons(0);

	private final BigDecimal amount;

	public static Money wons(long amount) {
		return new Money(BigDecimal.valueOf(amount));
	}

	public static Money wons(double amount) {
		return new Money(BigDecimal.valueOf(amount));
	}

	public static <T> Money sum(Collection<T> bags, Function<T, Money> monetary) {
		return bags.stream().map(bag -> monetary.apply(bag)).reduce(Money.ZERO, Money::plus);
	}

	Money(BigDecimal amount) {
		this.amount = amount;
	}

	public Money plus(Money amount) {
		return new Money(this.amount.add(amount.amount));
	}

	public Money minus(Money amount) {
		return new Money(this.amount.subtract(amount.amount));
	}

	public Money times(double percent) {
		return new Money(this.amount.multiply(BigDecimal.valueOf(percent)));
	}

	public Money divide(double divisor) {
		return new Money(amount.divide(BigDecimal.valueOf(divisor)));
	}

	public boolean isLessThan(Money other) {
		return amount.compareTo(other.amount) < 0;
	}

	public boolean isGreaterThan(Money other) {
		return amount.compareTo(other.amount) > 0;
	}

	public BigDecimal getAmount() {
		return amount;
	}

	public Long longValue() {
		return amount.longValue();
	}

	public Double doubleValue() {
		return amount.doubleValue();
	}

	public boolean equals(Object object) {
		if (this == object) {
			return true;
		}

		if (!(object instanceof Money)) {
			return false;
		}

		Money other = (Money)object;
		return Objects.equals(amount.doubleValue(), other.amount.doubleValue());
	}

	public int hashCode() {
		return Objects.hashCode(amount);
	}

	public String toString() {
		return amount.toString() + "원";
	}
}

@Converter(autoApply = true)
public class MoneyConverter implements AttributeConverter<Money, Long> {
	@Override
	public Long convertToDatabaseColumn(Money money) {
		return money.getAmount().longValue();
	}

	@Override
	public Money convertToEntityAttribute(Long amount) {
		return Money.wons(amount);
	}
}