Software Architecture in Java: Design & Development/

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Develop the Business Service Tier

Develop the Business Service Tier

Let's see how the business service can be developed for a one-to-one self-referencing relationship scenario.

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 ...