Our implementation of ICommandServiceInterceptor to evaluate validationrules before the command gets executed

gistfile1.cs

public class ValidateCommandInterceptor : ICommandServiceInterceptor
{
    private readonly IValidatorFactory _factory;
    private readonly ILog _logger = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);

    public ValidateCommandInterceptor(IValidatorFactory validatorFactory = null)
    {
        _factory = validatorFactory ?? new AttributedValidatorFactory();
    }

    public void OnBeforeBeforeExecutorResolving(CommandContext context)
    {
        // Nothing
    }

    public void OnBeforeExecution(CommandContext context)
    {
        var validator = _factory.GetValidator(context.TheCommandType);
        if (validator != null)
        {
            var result = validator.Validate(context.TheCommand);
            if (!result.IsValid)
            {
                var message = string.Format("Command validation failed on command {0}{1}", context.TheCommandType, CreateValidationSummary(result));
                _logger.ErrorFormat(message);
                throw new CommandParameterValidationException(message);
            }
        }
    }

    public void OnAfterExecution(CommandContext context)
    {
        // Nothing
    }

    private static string CreateValidationSummary(ValidationResult result)
    {
        if (result.IsValid)
            return string.Empty;

        var sb = new StringBuilder(result.Errors.Count);
        foreach (var failure in result.Errors)
        {
            sb.AppendLine();
            sb.AppendFormat(" (*) Property {0}: {1}", failure.PropertyName, failure.ErrorMessage);
        }
        return sb.ToString();
    }
}