工厂方法模式

标签：工厂方法模式

实例：

实现一个简单地计算器

UML类图：

实现代码：

    /// 运算类
    class Operation
    {
        private double _numberA = 0;
        private double _numberB = 0;

        public double NumberA
        {
            get { return _numberA; }
            set { _numberA = value; }
        }

        public double NumberB
        {
            get { return _numberB; }
            set { _numberB = value; }
        }

        /// 得到运算结果
        public virtual double GetResult()
        {
            double result = 0;
            return result;
        }
    }

    /// 加法类
    class OperationAdd : Operation
    {
        public override double GetResult()
        {
            double result = 0;
            result = NumberA + NumberB;
            return result;
        }
    }

    /// 减法类
    class OperationSub : Operation
    {
        public override double GetResult()
        {
            double result = 0;
            result = NumberA - NumberB;
            return result;
        }
    }
 
    /// 乘法类
    class OperationMul : Operation
    {
        public override double GetResult()
        {
            double result = 0;
            result = NumberA * NumberB;
            return result;
        }
    }
 
    /// 除法类
    class OperationDiv : Operation
    {
        public override double GetResult()
        {
            double result = 0;
            if (NumberB == 0)
                throw new Exception("除数不能为0。");
            result = NumberA / NumberB;
            return result;
        }
    }

    /// 工厂方法
    interface IFactory
    {
        Operation CreateOperation();
    }

    /// 专门负责生产“+”的工厂
    class AddFactory : IFactory
    {
        public Operation CreateOperation()
        {
            return new OperationAdd();
        }
    }

    /// 专门负责生产“-”的工厂
    class SubFactory : IFactory
    {
        public Operation CreateOperation()
        {
            return new OperationSub();
        }
    }

    /// 专门负责生产“*”的工厂
    class MulFactory : IFactory
    {
        public Operation CreateOperation()
        {
            return new OperationMul();
        }
    }

    /// 专门负责生产“/”的工厂
    class DivFactory : IFactory
    {
        public Operation CreateOperation()
        {
            return new OperationDiv();
        }
    }

    IFactory operFactory = new AddFactory();
    Operation oper = operFactory.CreateOperation();
    oper.NumberA = 1;
    oper.NumberB = 2;
    double result=oper.GetResult();

说明：

参考资料

-《大话设计模式》

工厂方法模式

标签：工厂方法模式

原文地址：http://blog.csdn.net/junjun150013652/article/details/45194287