设计模式学习笔记——抽象工厂

1.特点：当工厂方法无法满足多系列问题时，再重构为抽象工厂。

2.概念：抽象工厂模式为一个产品家族提供了统一的创建接口。当需要这个产品家族的某一系列的时候，可以从抽象工厂中选出相对应的系列来创建一个具体的工厂类别。

3.类图：

4.程序实现：

/// <summary>
    /// 抽象工厂类
    /// </summary>
    public interface IDatabaseFactory
    {

        IEmployee CreateEmployee();

        IUser CreateUser();
    }
/// <summary>
    /// 与SqlServer相关产品的实现
    /// </summary>
    public class SqlServerDatabaseFactory : IDatabaseFactory
    {

        public IEmployee CreateEmployee()
        {

            return new SqlEmployee();
        }

        public IUser CreateUser()
        {

            return new SqlUser();
        }

    }

    /// <summary>
    /// 与Access相关产品的实现
    /// </summary>
    public class AccessDatabaseFactory : IDatabaseFactory
    {

        public IEmployee CreateEmployee()
        {

            return new AccessEmployee();
        }

        public IUser CreateUser()
        {

            return new AccessUser();
        }

    }
/// <summary>
    /// 抽象产品
    /// </summary>
    public interface IUser
    {
        User GetUser();

        bool SaveUser();
    }

    /// <summary>
    /// 抽象产品
    /// </summary>
    public interface IEmployee
    {

        Employee GetEmployee();

        bool SaveEmployee();
    }
/// <summary>
    /// 与SqlServer相关的具体产品User
    /// </summary>
    public class SqlUser : IUser
    {
        public User GetUser()
        {

            return null;
        }

        public bool SaveUser()
        {

            return false;
        }

    }

    /// <summary>
    /// 与SqlServer相关的具体产品Employee
    /// </summary>
    public class SqlEmployee : IEmployee
    {

        public SqlEmployee()
        {

        }

        public Employee GetEmployee()
        {

            return null;
        }

        public bool SaveEmployee()
        {

            return false;
        }

    }

    /// <summary>
    /// 与Access相关的具体产品User
    /// </summary>
    public class AccessUser : IUser
    {

        public AccessUser()
        {

        }

        public User GetUser()
        {

            return null;
        }

        public bool SaveUser()
        {

            return false;
        }

    }

    /// <summary>
    /// 与Access相关的具体产品Employee
    /// </summary>
    public class AccessEmployee : IEmployee
    {

        public AccessEmployee()
        {

        }

        public Employee GetEmployee()
        {

            return null;
        }

        public bool SaveEmployee()
        {

            return false;
        }

    }