Software--电商平台--Module 5 Order & Payment

2018-01-10  14:11:30

电商平台 订购和支付 模块

一： 整体示意图

二：构建一个框架来处理 领域模型内部发生的事情--领域事件

1. IDomainEvent 标识模型中的 DomainEvent
2. IDomainEventHandler<T> where T : IDomainEvent 事件处理程序必须实现的接口。
3. IDomainEventHandlerFactory 用来获取给定领域事件的处理程序的集合
4. IEnumerableExtension 获取到 IDomainEventHandler 集合之后， 调用它们的处理方法并将领域事件作为动作的实参。

   using System;
   using System.Collections.Generic;
   using System.Linq;
   using System.Text;
   
   namespace Agathas.Storefront.Infrastructure.Domain.Events
   {
       public static class IEnumerableExtensions
       {
           public static void ForEach<T>(this IEnumerable<T> source, Action<T> action)
           {
               foreach (T item in source)
                   action(item);
           }
       }
   
   }

5. 静态类 DomainEvents -- 为了引发事件。

　　支持领域事件所需的框架。

　　

　

二 ： 领域对象 

1. Payment  值对象， 继承自 Infrastructure  -- ValueObjectBase　　  
2. OrderItem 实体  继承自 EntityBase<int> 
3. 与OrderItem 相关联的 Order 

EntityBase<int>

using System.Collections.Generic;

namespace Agathas.Storefront.Infrastructure.Domain
{
    public abstract class EntityBase<TId>
    {
        private List<BusinessRule> _brokenRules = new List<BusinessRule>();

        public TId Id { get; set; }

        protected abstract void Validate();

        public IEnumerable<BusinessRule> GetBrokenRules()
        {
            _brokenRules.Clear();
            Validate();
            return _brokenRules;
        }

        protected void AddBrokenRule(BusinessRule businessRule)
        {
            _brokenRules.Add(businessRule);
        }

        public override bool Equals(object entity)
        {
            return entity != null
               && entity is EntityBase<TId>
               && this == (EntityBase<TId>)entity;
        }

        public override int GetHashCode()
        {
            return this.Id.GetHashCode();
        }

        public static bool operator ==(EntityBase<TId> entity1,
           EntityBase<TId> entity2)
        {
            if ((object)entity1 == null && (object)entity2 == null)
            {
                return true;
            }

            if ((object)entity1 == null || (object)entity2 == null)
            {
                return false;
            }

            if (entity1.Id.ToString() == entity2.Id.ToString())
            {
                return true;
            }

            return false;
        }

        public static bool operator !=(EntityBase<TId> entity1,
            EntityBase<TId> entity2)
        {
            return (!(entity1 == entity2));
        }
    }

}

ValueObjectBase

using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Agathas.Storefront.Infrastructure.Domain
{
    public abstract class ValueObjectBase
    {
        private List<BusinessRule> _brokenRules = new List<BusinessRule>();

        public ValueObjectBase()
        {
        }

        protected abstract void Validate();

        public void ThrowExceptionIfInvalid()
        {
            _brokenRules.Clear();
            Validate();
            if (_brokenRules.Count() > 0)
            {
                StringBuilder issues = new StringBuilder();
                foreach (BusinessRule businessRule in _brokenRules)
                    issues.AppendLine(businessRule.Rule);

                throw new ValueObjectIsInvalidException(issues.ToString());
            }
        }

        protected void AddBrokenRule(BusinessRule businessRule)
        {
            _brokenRules.Add(businessRule);
        }
    }
}