Wsrtjtyk

I am doing a project and i need to implement some denormalizations. Specifically i need to query Projects by taskCount and/or projectTotalCost.
This is what i have so far.
Seems to me like it works, but i'm not sure anymore. I'm afraid it is prone to race conditions and things like that. Specifically the parts where i update the counters.
Even though i'm using transactions inside my service, i'm not sure about transaction IsolationLevels.
Is this ok ? Do i need to add something else ? Should i use @Version as well (beside transactions) ?
I really need to maintain this denormalization (taskCount, projectTotalCost) and keep it consistent.

@Entity

@Data

public class Project {



    @Id

    @GeneratedValue(strategy = GenerationType.IDENTITY)

    private Long id;



    @OneToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL, orphanRemoval = true)

    @JoinColumn(name = "project_id", referencedColumnName = "id")

    private List<Task> tasks;



    private int taskCount;

    private double projectTotalCost;



    public Project() {



        this.tasks = new ArrayList<>();

        this.taskCount = 0;

        this.projectTotalCost = 0;



    }



    public void addTask(Task t) {



        this.tasks.add(t);

        updateTaskCount();

        updateProjectCost();



    }



    public void removeTask(Task t) {



        this.tasks.remove(t);

        updateTaskCount();

        updateProjectCost();



    }



    public void removeWhere(Predicate<Task> spec) {



        this.tasks.removeIf(spec);

        updateTaskCount();

        updateProjectCost();



    }



    private void updateTaskCount() {

        this.taskCount = this.tasks.size();

    }



    private void updateProjectCost() {

        this.projectTotalCost = this.tasks.stream().mapToDouble((Task t) -> t.getCost()).sum();

    }



}







@Entity

@Data

public class Task {



    @Id

    @GeneratedValue(strategy = GenerationType.IDENTITY)

    private Long id;



    private String name;

    private String description;



    private double cost;



    public Task(String name, String description, double cost) {

        this.name = name;

        this.description = description;

        this.cost = cost;

    }



    public double getCost() {

        return this.cost;

    }



}









@Service

public class ProjectService {



    @Autowired

    private ProjectRepository repo;



    @Transactional

    public Project create(Project p) {



        return this.repo.save(p);



    }



    @Transactional

    public Project addTask(long projectId, Task t) {



        Project p = this.repo.findById(projectId);



        p.addTask(t);



        return repo.save(p);



    }



    @Transactional

    public Project removeTaskFromProject(long projectId, long taskId) {



        Project p = this.repo.findById(projectId);



        p.removeWhere((Task t) -> t.hasId(taskId));



        return repo.save(p);



    }



}