Create Task List Dto

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Now that we have our TaskDto, we need to create a DTO for our TaskList. Like with TaskDto, we'll use a Java record to create an immutable data class that represents a TaskList in our API.

Let's create our TaskListDto in the same com.devtiro.tasks.domain.dto package:

package com.devtiro.tasks.domain.dto;

import java.util.List;
import java.util.UUID;

public record TaskListDto(
        UUID id,
        String title,
        String description,
        Integer count,
        Double progress,
        List<TaskDto> tasks
) { }

Let's break down what we've included in our TaskListDto:

id - The UUID identifier of the task list
title - The task list's title
description - The task list's description
count - The number of tasks in this list
progress - A number between 0 and 1 representing completion percentage
tasks - The list of tasks belonging to this task list

Notice what we've included and excluded compared to our TaskList entity:

Included

Basic identifiers (id, title, description)
List of tasks using our TaskDto
Additional computed fields (count, progress) that aren't in the entity

Excluded

No created or updated timestamps - these are internal concerns
No JPA annotations - DTOs are pure data carriers
No bidirectional relationship management - that's handled at the entity level

The count and progress fields are particularly interesting as they're computed values that we'll calculate when converting from entity to DTO. This is a good example of how DTOs can include derived data that's useful for the client but isn't directly stored in our domain model.

By using a record, Java automatically provides us with:

All-args constructor
Getter methods for each field
equals() and hashCode() methods
toString() method
Immutability for all fields

This DTO will be used to:

Return task list data in API responses
Accept task list data in API requests
Transfer task list data between application layers

Summary

Created the TaskListDto record to represent task lists in our API
Included computed fields like count and progress
Embedded TaskDto objects for the tasks collection
Used Java records for automatic getter methods and immutability
Excluded internal implementation details like timestamps