I have a scenario where I want to filter, sort and page over a result where 3 tables take part.
At the moment I use Spring Data JPA's Specification feature to do it on a single entity: repository.findAll(specification, pageRequest).
This works great, but now I have another scenario where the sort / filter attributes are spread over 3 tables which are connected by one-to-many relations.
Here is my scenario:
@Entity
public class CustomerEntity ... {
...
@Column(nullable = false)
public String customerNumber;
@OneToMany(mappedBy = "customer", cascade = CascadeType.ALL, orphanRemoval = true)
public List<CustomerItemEntity> items;
}
@Entity
public class CustomerItemEntity ... {
...
@Column(nullable = false)
public String itemNumber;
@ManyToOne(optional = false)
@JoinColumn(name = "customerId")
public CustomerEntity customer;
@OneToMany(mappedBy = "item", cascade = CascadeType.ALL, orphanRemoval = true)
public List<DocumentEntity> documents;
}
@Entity
public class DocumentEntity ... {
...
@Column(nullable = false)
public LocalDate validDate;
@ManyToOne(optional = false)
@JoinColumn(name = "itemId")
public CustomerItemEntity item;
}
Is there a way to use PageRequest and Specification where customerNumber, itemNumber and validDate are used for filtering, sorting and paging at the same time?
Try something like this:
Specification<CustomerEntity> joins = (customer, query, cb) -> {
// from CustomerEntity c
// join c.items i
Join<CustomerEntity, CustomerItemEntity> items = customer.join("items");
// join i.documents d
Join<CustomerItemEntity, DocumentEntity> documents = items.join("documents");
// // where c.customerNumber = ?1 and i.itemNumber = ?2 and d.validDate = ?3
return cb.and(
customer.equal(customer.get("customerNumber", customerNumber)),
items.equal(items.get("itemNumber", itemNumber)),
documents.equal(documents.get("validDate", validDate))
);
};
// sort by c.customerNumber asc
PageRequest pageRequest = new PageRequest(0, 2, new Sort(Sort.Direction.ASC, "customerNumber"));
Page<CustomerEntity> customerPage = CustomerRepo.findAll(joins, pageRequest);
But I don't know why do you need Specification here?
You can make the same more simpler:
@Query("select c from CustomerEntity c join c.items i join i.documents d where c.customerNumber = ?1 and i.itemNumber = ?2 and d.validDate = ?3")
Page<CustomerEntity> getCustomers(String customerNumber, String itemNumber, LocaleDate validDate, Pageable pageable);
But all this does not make sense since your three entities have sequential one-to-many associations. In this case instead of three conditions you can use only last one: where d.validDate = ?1. Then a query method became even easier:
@Query("select c from CustomerEntity c join c.items i join i.documents d where d.validDate = ?1")
Page<CustomerEntity> getCustomers(LocaleDate validDate, Pageable pageable);
UPDATE
To add sorting by a field of joined entity we can use orderBy method of the query:
Specification<CustomerEntity> joins = (customer, query, cb) -> {
Join<CustomerEntity, CustomerItemEntity> items = customer.join("items");
Join<CustomerItemEntity, DocumentEntity> documents = items.join("documents");
// Ascending order by 'Document.itemNumber'
query.orderBy(cb.asc(documents.get("itemNumber")));
return cb.and(
customer.equal(customer.get("customerNumber", customerNumber)),
items.equal(items.get("itemNumber", itemNumber)),
documents.equal(documents.get("validDate", validDate))
);
};
Page<CustomerEntity> customerPage = CustomerRepo.findAll(joins, new PageRequest(0, 2));
To sort by several parameters you can pass them to the method separated by commas or by a List:
query.orderBy(cb.asc(items.get("customerNumber")), cb.desc(documents.get("itemNumber")));