java - 用于查找最新状态的 Spring Data JPA 规范

Question

我正在尝试创建一个规范来根据他们的最新状态（可用、不可用）过滤人们。考虑以下实体。

public class Person{
    @Id
    private Long id;

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

    @OneToMany(mappedBy = "person")
    private Set<Status> statuses = new HashSet<>();
}

public class Status{

    @Id
    private Long id;

    @Column(name = "created_at")
    private Instant createdAt;

    @ManyToOne
    private StatusType statusType;
}

public class StatusType{

    @Id
    private Long id;

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

    @OneToMany(mappedBy = "statusType")
    private Set<Status> statuses = new HashSet<>();
}

在这个问题的帮助下，我创建了以下规范来根据他们的状态类型过滤一个人。

specification =
  specification.and(
    buildJoinSpecification(
      criteria.getStatusTypeId(),
      Person_.statuses,
      Status_.statusType,
      StatusType_.id
    )
  );

我知道我必须greatest在createdAt内部使用，Status但我无法弄清楚语法。这是我的buildJoinSpecification.

private <REFERENCE, JOIN, FILTER extends Comparable<? super FILTER>> Specification<Person> buildJoinSpecification(
        RangeFilter<FILTER> filter,
        SetAttribute<? super Person, REFERENCE> reference,
        SingularAttribute<REFERENCE, JOIN> joinField,
        SingularAttribute<JOIN, FILTER> valueField
    ) {
        Specification<Person> result = Specification.where((Specification) null);
        if (filter.getEquals() != null) {
            result = this.equalsSpecification(reference, joinField, valueField, filter.getEquals());
        }
        if (filter.getIn() != null) {
            result = this.valueIn(reference, joinField, valueField, filter.getIn());
        }
        return result;
    }

    private <REFERENCE, JOIN, FILTER> Specification<Person> equalsSpecification(
        SetAttribute<? super Person, REFERENCE> reference,
        SingularAttribute<REFERENCE, JOIN> joinField,
        SingularAttribute<JOIN, FILTER> idField,
        FILTER value
    ) {
        return (root, query, builder) -> builder.equal(root.join(reference).join(joinField).get(idField), value);
    }

    private <REFERENCE, JOIN, FILTER> Specification<Person> valueIn(
        SetAttribute<? super Person, REFERENCE> reference,
        SingularAttribute<REFERENCE, JOIN> joinField,
        SingularAttribute<JOIN, FILTER> valueField,
        Collection<FILTER> values
    ) {
        return (root, query, builder) -> {
            CriteriaBuilder.In<FILTER> in = builder.in(root.join(reference).join(joinField).get(valueField));
            for (FILTER value : values) {
                in = in.value(value);
            }
            return in;
        };
    }

我将不胜感激任何帮助。谢谢。