CODEWITHSUNDEEP
c#
Tomaltach
Tomaltach

Reputation: 923

Is Object created before or after method calls?

I have three different databases that I need to check that I am connected to. This is what I originally have, which works perfectly fine.

public async Task<ServiceAvailabilityDTO> ServiceAvailabilityStatus()
{
    return new ServiceAvailabilityDTO
    {
        IsDb1Online = await IsDb1Available(),
        IsDb2Online = IsDb2Available(),
        IsDb3Online = await IsDb3Available()
    };
}

private async Task<bool> IsDb1Available()
{
    var count = await _db1Service.GetDbCount();
    if (count > 0)
        return true;

    return false;
}

private bool IsDb2Available()
{
    if (_db2Service.GetDbCount() > 0)
        return true;

    return false;
}

private async Task<bool> IsDb3Available()
{
    var pong = await _db3Provider.PingDb();
    if(pong.Success == true && pong.Version != null)
        return true;

    return false;
}

Now however, I need to log exception messages in my DTO for each DB check.

public async Task<ServiceAvailabilityDTO> ServiceAvailabilityStatus()
{
    return new ServiceAvailabilityDTO
    {
        IsDb1Online = await IsDb1Available(),
        IsDb2Online = IsDb2Available(),
        IsDb3Online = await IsDb3Available(this) // This is an example. I want to pass the reference of **ServiceAvailabilityDTO** to **IsDb3Available**
    };
}

private async Task<bool> IsDb3Available(ServiceAvailabilityDTO availability)
{
    try
    {
        var pong = await _db3Provider.PingDb();
        if(pong.Success == true && pong.Version != null)
            return true;

        return false;
    }
    catch (Exception e)
    {
        var exceptionMessage = e.Message;
        if (e.InnerException != null)
        {
            // This is what I hope to put into the object reference
            exceptionMessage = String.Join("\n", exceptionMessage, e.InnerException.Message);
            availability.db3Exception = exceptionMessage ;
        }

        return false;
    }
}

My question is;

  1. Can I keep my return method the same as in the first example, and pass the object reference to each method to store the exception and still return my bool value.

  2. Or does the object not get created until all of the method calls have happened, and then create the object with the returned values?

I know I could just create the object normally and pass it in each method call, but it is specifically this way of doing it that has inspired me to ask this question, purely to be informed and learn from.

Thanks.

Upvotes: 0

Views: 66

Answers (1)

Jamiec
Jamiec

Reputation: 136074

No, you cannot do it like this because in the context of what you're doing this does not refer to the object you're populating, it refers to the object containing the method you're calling.

public async Task<ServiceAvailabilityDTO> ServiceAvailabilityStatus()
{
    return new ServiceAvailabilityDTO
    {
        IsDb1Online = await IsDb1Available(),
        IsDb2Online = IsDb2Available(),
        IsDb3Online = await IsDb3Available(this) // here 'this' does NOT ref to ServiceAvailabilityDTO
    };
}

There is no keyword which does refer to ServiceAvailabilityDTO either, so you're left with creating the object, and passing it to each method. At this point, I dont think there is much point you returning the boolean either - you may as well set the boolean property in line

public async Task<ServiceAvailabilityDTO> ServiceAvailabilityStatus()
{
    var sa = new ServiceAvailabilityDTO();
    await CheckDb1Available(sa);
    CheckDb2Available(sa);
    await CheckDb3Available(sa);
    return sa;
}

(Note I've renamed the methods from Is* to Check* as the former implies a return boolean, the latter implies something going on inline.)

Upvotes: 1

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