A KISS approach for specification pattern. http://en.wikipedia.org/wiki/Specification_pattern
PM> Install-Package KissSpecifications
- Create your specification classes:
public class CustomerNameSpecification : SpecificationBase<string>
{
#region Constants
public const int MinCustomerName = 5;
public const int MaxCustomerName = 30;
#endregion
#region Methods
public override bool IsSatisfiedBy(string target)
{
if (String.IsNullOrWhiteSpace(target))
{
NotSatisfiedReason = "Customer name should be specified.";
return false;
}
if (target.Length < MinCustomerName)
{
NotSatisfiedReason = String.Format(CultureInfo.CurrentUICulture, "The minimum length for customer name is {0} chars.", MinCustomerName);
return false;
}
if (target.Length > MaxCustomerName)
{
NotSatisfiedReason = String.Format(CultureInfo.CurrentUICulture, "The maximum length for customer name is {0} chars.", MaxCustomerName);
return false;
}
return true;
}
#endregion
}public class CustomerNameSpecification : SpecificationBase<string>
{
#region Constants
public const int MinCustomerName = 5;
public const int MaxCustomerName = 30;
#endregion
#region Methods
public override bool IsSatisfiedBy(string target)
{
if (String.IsNullOrWhiteSpace(target))
{
NotSatisfiedReason = "Customer name should be specified.";
return false;
}
if (target.Length < MinCustomerName)
{
NotSatisfiedReason = String.Format(CultureInfo.CurrentUICulture, "The minimum length for customer name is {0} chars.", MinCustomerName);
return false;
}
if (target.Length > MaxCustomerName)
{
NotSatisfiedReason = String.Format(CultureInfo.CurrentUICulture, "The maximum length for customer name is {0} chars.", MaxCustomerName);
return false;
}
return true;
}
#endregion
}- Call the SpecificationService on your Domain method:
public static class CustomerService
{
public static void CreateCustomer(Customer customer)
{
SpecificationService.ThrowIfAnySpecificationIsNotSatisfiedBy(customer, new CustomerCreationSpecification());
// TODO: Logic to create customer...
}
}