Building Queries with Spring Data JPA - Spring Data - page 64

The source code of the relevant methods is given as follows:

private Pageable buildPageSpecification(int pageIndex, int pageSize) {
Sort sortSpec = sortByLastNameAndFirstNameAsc();
return new PageRequest(pageIndex, pageSize, sortSpec);
}

private Sort sortByLastNameAndFirstNameAsc() {
return new Sort(new Sort.Order(Sort.Direction.ASC, "lastName"),
new Sort.Order(Sort.Direction.ASC, "firstName")
);
}

Implementing pagination
In order to paginate the results of our queries, we have to pass the created
PageRequest object to a correct repository method. This method depends on the
approach, which we are using to build our queries. Each of these approaches is
described in this subsection.

JpaRepository
Because the ContactRepository extends the JpaRepository<T,ID> interface, we
got access to the Page<Contact> findAll(Pageable page) method that we can
use to paginate the list of all entities. The implementation of the findAllForPage()
method of the RepositoryContactService class is described as follows:

1. We get the used PageRequest object.

2. We get a reference to Page<Contact> by calling the repository method and

passing the PageRequest object as parameter.

3. We return a list of contacts.

The source code of our findAllForPage() method is given as follows:

@Transactional(readOnly = true)
@Override
public List<Contact> findAllForPage(int pageIndex, int pageSize) {
Pageable pageSpecification = buildPageSpecification(pageIndex,
pageSize);

Page<Contact> page = repository.findAll(pageSpecification);

return page.getContent();
}