TaskFlow integration sprint — the instructions start to fade

Goal. POST /tasks with an empty or missing title returns HTTP 400 (Bad Request), not a saved task with a blank title.

• POST {"title":"","done":false} → 400.
• POST {"title":"Real task"} → 200 and it saves.

Steps (clear):

1. Add the validation starter

   Add spring-boot-starter-validation to pom.xml and reload.

2. Constrain the DTO field

   Put @NotBlank on the request's title.

3. Turn validation on at the controller

   Add @Valid before @RequestBody.

import jakarta.validation.constraints.NotBlank;

public record TaskRequest(@NotBlank String title, boolean done) { }

import jakarta.validation.Valid;

@PostMapping
public Task create(@Valid @RequestBody TaskRequest req) {
    return service.create(req.title());
}

Goal. A task has a priority (an int, default 3). You can set it on create/update, and it comes back in every response.

• POST with "priority": 1 saves and returns it.
• POST without priority defaults to 3.
• The H2 TASKS table has a priority column.

Which layers? (named for you this time — the fade begins) Model (new field), DTO (accept it), Service (pass it through, apply the default), Controller (no change if the DTO carries it). The repository is untouched — JPA adds the column automatically.

private int priority;   // add the field (+ Lombok generates the accessor)

public record TaskRequest(@NotBlank String title, boolean done, Integer priority) { }

public Task create(String title, Integer priority) {
    Task t = new Task();
    t.setTitle(title);
    t.setDone(false);
    t.setPriority(priority == null ? 3 : priority);   // the default rule, one home
    return repository.save(t);
}

Goal. GET /tasks/open returns tasks where done=false, sorted by priority ascending (1 = most urgent, first).

• Only not-done tasks appear.
• They're ordered by priority, 1 before 3.
• The sorting/filtering is a repository or service concern, not done in the controller.

List<Task> findByDoneFalseOrderByPriorityAsc();

// service
public List<Task> openByPriority() { return repository.findByDoneFalseOrderByPriorityAsc(); }
// controller
@GetMapping("/open")
public List<Task> open() { return service.openByPriority(); }

Goal. GET /tasks?page=0&size=5 returns at most 5 tasks and metadata about total pages.

• With 12 tasks, page=0&size=5 returns 5; page=2 returns 2.
• The response includes total element/page counts.

// service
public Page<Task> page(Pageable pageable) { return repository.findAll(pageable); }
// controller  (import org.springframework.data.domain.*)
@GetMapping("/paged")
public Page<Task> paged(Pageable pageable) { return service.page(pageable); }

Goal. A user can find tasks whose title contains a piece of text, case-insensitively.

• Searching "milk" finds "Buy milk" and "MILK run".
• Searching something absent returns an empty list, not an error.
• You chose a sensible URL and put the query at the repository seam.

// repository
List<Task> findByTitleContainingIgnoreCase(String q);
// service
public List<Task> search(String q) { return repository.findByTitleContainingIgnoreCase(q); }
// controller
@GetMapping("/search")
public List<Task> search(@RequestParam String q) { return service.search(q); }

Goal. A task can have a dueDate. There's a way to list all tasks that are past due and still not done.

• You can create a task with a due date and read it back.
• An endpoint returns only tasks with dueDate < today and done=false.
• Tasks with no due date never count as overdue.

// model: private LocalDate dueDate;   (nullable — no annotation needed)
// repository
List<Task> findByDoneFalseAndDueDateBefore(LocalDate date);
// service
public List<Task> overdue() { return repository.findByDoneFalseAndDueDateBefore(LocalDate.now()); }
// controller
@GetMapping("/overdue")
public List<Task> overdue() { return service.overdue(); }