Some of the base concepts/code of this project comes from the great book : Professional ASP.NET Design Patterns by : Scott Millett
The main goal of the project is to give you a base when you are working with Domain Driven Design.
##Project Overview
- Entity
- Value Object
- Custom Validation Checks
- Validate Value Object
- Validate Entity Extensions
- IValidate Entity
- Validate Entity Test Stub Factory
###Entity The base class for Entities is EntityBase. This class includes an Id property using genercis so that you can use whatever type you want. It also inludes an abstract CheckForBrokenRules where you ensure your entity is valid.
public abstract class EntityBase<TId>{
private readonly IList<BrokenRule> _brokenRules = new List<BrokenRule>();
public TId Id { get; set; }
public IEnumerable<BrokenRule> GetBrokenRules{
get{
_brokenRules.Clear();
CheckForBrokenRules();
return _brokenRules;
}
}
public IList<BrokenRule> BrokenRules {get { return _brokenRules; }}
protected abstract void CheckForBrokenRules();
}###Value Object The base class for Value Objects is ValueObject This class includes an abstract CheckForBrokenRules where you ensure your value object is valid.
public abstract class ValueObject{
private readonly IList<BrokenRule> _brokenRules = new List<BrokenRule>();
public IEnumerable<BrokenRule> GetBrokenRules
{
get
{
_brokenRules.Clear();
CheckForBrokenRules();
return _brokenRules;
}
}
public IList<BrokenRule> BrokenRules { get { return _brokenRules; } }
protected abstract void CheckForBrokenRules();
}###Custom Validation Checks There are some built in custom validation checks that will add built-in broken rule objects to an entity's broken rule list
protected override void CheckForBrokenRules(){
BrokenRules
.AddIfPropertyIsNull(TestStringProperty, () => TestStringProperty);
BrokenRules
.AddIfPropertyEmpty(TestStringProperty, () => TestStringProperty);
BrokenRules
.AddIfIntegerPropertyLessThanOne(TestIntProperty,() => TestIntProperty);
}###Validate Value Object These are extension methods that allow you to find out if a Value Object is in a valid state or to throw an exeption if invalid.
public static class ValidateValueObject{
public static bool IsValid(this ValueObject valueObject)
{
return valueObject.GetBrokenRules.HasNoBrokenRules();
}
public static void ThrowExceptionIfEntityIsInvalid(this ValueObject valueObject)
{
ThrowException(valueObject.GetBrokenRules);
}
private static void ThrowException(IEnumerable<BrokenRule> brokenRules)
{
if (!brokenRules.Any())
{
return;
}
var message = brokenRules.GetInvalidDomainObjectExceptionMessage();
throw new ValueObjectIsNotValidException(message);
}
}###Validate Entity Extensions These are extension methods that allow you to find out if an entity is in a valid state or to throw an exeption if an entity is invalid. This currently only works with string, guid and integer ids for entities
####IsValid Method
return entity.GetBrokenRules.HasNoBrokenRules();####ThrowException Method
ThrowException(entity.GetBrokenRules);
private static void ThrowException(IEnumerable<BrokenRule> brokenRules){
if (!brokenRules.Any())
{
return;
}
var message = brokenRules.GetInvalidDomainObjectExceptionMessage();
throw new EntityIsNotValidException(message);
}
###IValidate Entity This provides an interface that allows you program to an interface as opposed to a concrete implementation. The included concrete implementation ValidateEntity calls the corresponding methods from ValidateEntityExtensions. This currently only works with string, guid and integer ids for entities
public interface IValidateEntity
{
bool IsValid(EntityBase<int> entity);
bool IsValid(EntityBase<string> entity);
bool IsValid(EntityBase<Guid> entity);
IEnumerable<string> GetErrorMessages(EntityBase<int> entity);
IEnumerable<string> GetErrorMessages(EntityBase<string> entity);
IEnumerable<string> GetErrorMessages(EntityBase<Guid> entity);
void ThrowExceptionIfEntityIsInvalid(EntityBase<int> entity);
void ThrowExceptionIfEntityIsInvalid(EntityBase<string> entity);
void ThrowExceptionIfEntityIsInvalid(EntityBase<Guid> entity);
}###Validate Entity Test Stub Factory This factory class simplifies the creation of "Test Stubs" for IValidateEntity. The only one that may seem odd is ValidateEntityInNotValidStateNoExceptionStub; the point of this one is that it allows you to perfrom state verification on your entity without having your test fail because of an exception
ValidateEntityStubFactory
.CreateValidateEntity(ValidateEntityStubType.IsValid);ValidateEntityStubFactory
.CreateValidateEntity(ValidateEntityStubType.NotValidAndShouldNotThrowException);ValidateEntityStubFactory
.CreateValidateEntity(ValidateEntityStubType.NotValidAndThrowsException);