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The GetOrderStatusUseCase retrieves all tasks associated with an order and calculates the overall order status by analyzing the state of each task.

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Input Port

The use case implements the GetOrderStatusPort interface: 
public interface GetOrderStatusPort {
    TaskStatus execute(Long orderId);
}

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Implementation

GetOrderStatusUseCase.java
package com.foodtech.kitchen.application.usecases;

import com.foodtech.kitchen.application.exepcions.OrderNotFoundException;
import com.foodtech.kitchen.application.ports.in.GetOrderStatusPort;
import com.foodtech.kitchen.application.ports.out.TaskRepository;
import com.foodtech.kitchen.domain.model.Task;
import com.foodtech.kitchen.domain.model.TaskStatus;
import com.foodtech.kitchen.domain.services.OrderStatusCalculator;

import java.util.List;

public class GetOrderStatusUseCase implements GetOrderStatusPort {

    private final TaskRepository taskRepository;
    private final OrderStatusCalculator orderStatusCalculator;

    public GetOrderStatusUseCase(TaskRepository taskRepository,
                                 OrderStatusCalculator orderStatusCalculator) {
        this.taskRepository = taskRepository;
        this.orderStatusCalculator = orderStatusCalculator;
    }

    @Override
    public TaskStatus execute(Long orderId) {
        List<Task> tasks = taskRepository.findByOrderId(orderId);

        // Validation: orderId must exist
        if (tasks.isEmpty()) {
            throw new OrderNotFoundException(orderId);
        }

        // Delegate business logic to domain
        return orderStatusCalculator.calculateOrderStatus(tasks);
    }
}

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Use Case Flow

1

Retrieve Tasks

Query the TaskRepository for all tasks associated with the given orderId.
2

Validate Order Exists

If no tasks are found, throw OrderNotFoundException since the order doesn’t exist.
3

Calculate Status

Delegate to OrderStatusCalculator which applies business rules:
  • COMPLETED: All tasks are completed
  • IN_PREPARATION: At least one task has started but not all are completed
  • PENDING: No tasks have been started yet
4

Return Status

Return the calculated TaskStatus representing the order’s overall state.

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Status Calculation Logic

The OrderStatusCalculator applies these rules: 
public TaskStatus calculateOrderStatus(List<Task> tasks) {
    // All tasks completed → order completed
    if (areAllTasksCompleted(tasks)) {
        return TaskStatus.COMPLETED;
    }

    // At least one task started → order in preparation
    if (hasAnyTaskStarted(tasks)) {
        return TaskStatus.IN_PREPARATION;
    }

    // No tasks started → order pending
    return TaskStatus.PENDING;
}

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Example Usage

GetOrderStatusPort getOrderStatus = new GetOrderStatusUseCase(
    taskRepository,
    orderStatusCalculator
);

// Check status of order #42
TaskStatus status = getOrderStatus.execute(42L);

switch (status) {
    case PENDING:
        System.out.println("Order is waiting to be prepared");
        break;
    case IN_PREPARATION:
        System.out.println("Order is being prepared");
        break;
    case COMPLETED:
        System.out.println("Order is ready for delivery");
        break;
}

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Exceptions

If the provided orderId doesn’t exist (no associated tasks), the use case throws OrderNotFoundException.

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Dependencies

TaskRepository

Queries tasks by order ID

OrderStatusCalculator

Domain service that implements status calculation rules

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