Exercise: GLS Package Tracking System - Part 1

Scenario

GLS (Global Logistics Services) wants to develop a package tracking system to manage the delivery of packages. As part of the initial phase, they need to create a basic system using Java, JPA, and JPQL to manage package information.

Requirements

1. Create an entity named “Package” using Lombok to manage package information. The “Package” entity should have the following attributes:
   • ID (auto-generated primary key)
   • Tracking number (String)
   • Sender name (String)
   • Receiver name (String)
   • Delivery status (Enum: PENDING, IN_TRANSIT, DELIVERED)

2. Implement a DAO (Data Access Object) class named “PackageDAO” to perform CRUD operations on the “Package” entity using JPA.

3. Define pre-update and pre-persist life cycle methods in the “Package” entity to update the last updated timestamp automatically.

4. Implement methods in the “PackageDAO” to perform the following operations:
   • Persist a new package
   • Retrieve a package by its tracking number
   • Update the delivery status of a package
   • Remove a package from the system

5. Write JUnit tests for the DAO methods to ensure they work correctly.

6. Use Maven for project management.

Hints

• Use Jakarta Persistence (JPA) annotations to map the entity attributes to database columns.
• Implement JPQL queries for retrieving packages based on certain criteria, such as tracking number or delivery status.

1. JUnit Test Example:

@TestInstance(TestInstance.Lifecycle.PER_CLASS)
public class PackageDAOTest {
    
   private static PackageDao packageDao;
   private static EntityManagerFactory emfTest;


   @BeforeAll
   static void setUpAll() {
      emfTest = HibernateConfig.getEntityManagerFactory();
      hotelDao = HotelDao.getInstance(emfTest);
   }
   
    @AfterAll
    public static void tearDown() {
        entityManager.close();
    }

    @Test
    public void testPersistPackage() {
        Package pkg = new Package();
        pkg.setTrackingNumber("ABC123");
        pkg.setSenderName("Sender");
        pkg.setReceiverName("Receiver");
        pkg.setDeliveryStatus(DeliveryStatus.PENDING);

        packageDAO.persistPackage(pkg);

        // Retrieve the package from the database and assert its existence
        Package retrievedPackage = entityManager.find(Package.class, pkg.getId());
        Assertions.assertNotNull(retrievedPackage);
        Assertions.assertEquals("ABC123", retrievedPackage.getTrackingNumber());
    }

    // Implement other test methods for CRUD operations
}

Expected Outcome

This exercise should provide a solid foundation for understanding JPA (ORM) and JPQL in the context of building a package tracking system. In part 2, you can introduce more complex relationships between entities to further enhance the system.