Skip to main content

Coding Stories - string.Format and enum as const

Looking over some code this days I found the fallowing things.

1. Odd way of using string.Format
The fallowing code is extracted from an application:
Trace.WriteLine(string.Format("{0}{1}{2}{3}{4}{5}{6}", 
    "Generating ", 
    count, 
    " strings of size ",
    stringSize, 
    " took ", 
    duration, 
    " milliseconds."));
Trace.WriteLine(string.Format("{0}{1}{2}", 
    "Only ", 
    strings.Count, 
    " strings were generated due to uniqueness constraint."));
As we can see, ‘string.Format’ is overused. The code is not only hard to read and maintain, but the arguments are used everywhere, even when part of the string are constant. Even the spaces around words are fully missing from the format.
The above code should look something like this:
Trace.WriteLine(string.Format("Generation {0} strings of size {1} tool {2} milliseconds.", 
     count, 
     stringSize, 
     duration));
Trace.WriteLine(string.Format("Only {0} strings were generated due to uniqueness constraint.", 
     strings.Count));

2. Using ‘enum’ to manage int const
I was surprise to find this interesting way to declare const.
    public enum Constants
    {
        RandomStringSize = 2,
        Count = 500,
        KeyMaxValue = 1000,
        NumberOfReadings = 100000
    }
...
    public class FooSet
    {
        private const int count = (int)Constants.Count;
        private const int keyMaxValue = (int)Constants.KeyMaxValue;
        private const int numberOfReadings = (int)Constants.NumberOfReadings;
...
    }
    public class Car
    {
        private const int count = (int)Constants.Count;
        private const int keyMaxValue = (int)Constants.KeyMaxValue;
        private const int numberOfReadings = (int)Constants.NumberOfReadings;
...
    }
First of all why we would need to declare constants as an enum. Usually we are using enum when we have different states of possible values for a specific case. For example Color.Red, Color.Blue, Color.Black.
If we need to reuse const. in multiple location we could create a 'configuration' class that could contain this const (this class could be static). But keeping them as an enum.... hmmm.
There is a smell in the moment when we need to convert enum to int. What would happen if the const would be char or string? I don't want to imagine how you could convert it.
In this case, because the const are used in multiple classes (4 classes), without a direct connection between them, I would create a static class with this 4 const and use it directly where is needed. In this moment there is no need for mocking this value or changing them at runtime.  
    public static class RandomStringConstants
    {
        public const int RandomStringSize = 2;
        public const int Count = 500;
        public const int KeyMaxValue = 1000;
        public const int NumberOfReadings = 100000;
    }

Comments

Popular posts from this blog

How to check in AngularJS if a service was register or not

There are cases when you need to check in a service or a controller was register in AngularJS.
For example a valid use case is when you have the same implementation running on multiple application. In this case, you may want to intercept the HTTP provider and add a custom step there. This step don’t needs to run on all the application, only in the one where the service exist and register.
A solution for this case would be to have a flag in the configuration that specify this. In the core you would have an IF that would check the value of this flag.
Another solution is to check if a specific service was register in AngularJS or not. If the service was register that you would execute your own logic.
To check if a service was register or not in AngularJS container you need to call the ‘has’ method of ‘inhector’. It will return TRUE if the service was register.
if ($injector.has('httpInterceptorService')) { $httpProvider.interceptors.push('httpInterceptorService&#…

ADO.NET provider with invariant name 'System.Data.SqlClient' could not be loaded

Today blog post will be started with the following error when running DB tests on the CI machine:
threw exception: System.InvalidOperationException: The Entity Framework provider type 'System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer' registered in the application config file for the ADO.NET provider with invariant name 'System.Data.SqlClient' could not be loaded. Make sure that the assembly-qualified name is used and that the assembly is available to the running application. See http://go.microsoft.com/fwlink/?LinkId=260882 for more information. at System.Data.Entity.Infrastructure.DependencyResolution.ProviderServicesFactory.GetInstance(String providerTypeName, String providerInvariantName) This error happened only on the Continuous Integration machine. On the devs machines, everything has fine. The classic problem – on my machine it’s working. The CI has the following configuration:

TeamCity.NET 4.51EF 6.0.2VS2013
It seems that there …

Entity Framework (EF) TransactionScope vs Database.BeginTransaction

In today blog post we will talk a little about a new feature that is available on EF6+ related to Transactions.
Until now, when we had to use transaction we used ‘TransactionScope’. It works great and I would say that is something that is now in our blood.
using (var scope = new TransactionScope(TransactionScopeOption.Required)) { using (SqlConnection conn = new SqlConnection("...")) { conn.Open(); SqlCommand sqlCommand = new SqlCommand(); sqlCommand.Connection = conn; sqlCommand.CommandText = ... sqlCommand.ExecuteNonQuery(); ... } scope.Complete(); } Starting with EF6.0 we have a new way to work with transactions. The new approach is based on Database.BeginTransaction(), Database.Rollback(), Database.Commit(). Yes, no more TransactionScope.
In the followi…