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Software Architecture in Java: Design & Development

Develop the Business Service Tier

Explore the development of the business service tier focusing on one-to-one self-referencing relationships. This lesson helps you understand how to implement, test, and manage core operations such as fetching, creating, editing, and removing student entities along with their mentors, using mappers and data access layers within Java Spring and Hibernate environments.

We'll cover the following...

Let’s now jump to the business service tier.

Find all records operation

First, we will review the test for the “fetching all records” operation.

Java
@RunWith( SpringJUnit4ClassRunner.class )

@ContextConfiguration( locations = { "classpath:context.xml" } )

@TransactionConfiguration( defaultRollback = true )

@Transactional

public class StudentServiceImplTest {

	@Autowired

	private StudentService service ;

	@Test

	public void testFindAll() {

		Assert.assertEquals(0L, service.findAll().size());

	}

}

Let’s see how to code the matching method in the business service. We retrieve all the records using the data access operation and return a list of StudentDto using the mapper.

Java
@Service

@Transactional

public class StudentServiceImpl implements StudentService{

	@Autowired

	private StudentDao dao ;

	@Autowired

	private StudentMapper mapper ;

	@Override

	public List<StudentDto> findAll() {

		List<StudentDto> studentDTOs = new ArrayList<StudentDto>();

		List<Student> students = dao.getAll();

		if(null != students){

			for(Student student : students){

				studentDTOs.add(mapper.mapEntityToDto(student));

			}

		}

		return studentDTOs;

	}

}

Mappers

As discussed earlier, we have a mapper that converts data access objects into entities and vice-versa. It typically has two operations, mapDtoToEntity and mapEntityToDto ...