using System.Collections.Generic;

using System.Threading;

using System.Threading.Tasks;

​

//Implement Depedency Injection - Constructor Injection pattern on VehicleBusinessLogic class and decouple VehicleDataAccess implementation

​

/////////////////////////////////// BEGIN CODE CHANGES ///////////////////////////////////

public class VehicleBusinessLogic

{

    public VehicleBusinessLogic()

    {

    }

    // Retrieves list of vehicles based on criteria

    public Task<IEnumerable<Vehicle>> SearchVehicles(string make, string year, string model)

    {

        IVehicleDataAccess vehicleDataAccess = new VehicleDataAccess();

​

        return vehicleDataAccess.GetVehicles(make, year, model);

    }

}

/////////////////////////////////// END CODE CHANGES ///////////////////////////////////

​

​

public interface IVehicleDataAccess

{

    Task<IEnumerable<Vehicle>> GetVehicles(string make, string year, string model);

}

​

public class VehicleDataAccess : IVehicleDataAccess

{

    public async Task<IEnumerable<Vehicle>> GetVehicles(string make, string year, string model)

    {

        // Assume data retrieved thru repository / db / internal or external service

        return await Task.FromResult<List<Vehicle>>(new List<Vehicle>());

    }

}

​

​

public class Vehicle

{

    public int ID { get; set; }

    public string Make { get; set; }

    public string Year { get; set; }

    public string Model { get; set; }

}