设计模式 - 模板方法模式

一、模板方法模式

• AbstractClass 抽象类。

abstract class AbstractClass
{
//一些抽象行为，放到子类中去实现
  public abstract void PrimitiveOperation1();
  public abstract void PrimitiveOperation2();

  //模板方法，给出了逻辑的股价，而逻辑的组成是一些相应的抽象操作，它们都推迟到子类中去实现
  public void TemplateMethod()
{
  PrimitiveOperation1();
  PrimitiveOperation2();
  Console.WriteLine("");
}
}

• ConcreteClass 实现父类所定义的一个或多个抽象方法。每一个 AbstractClass 都可以有多个 ConcreteClass 与之对应，而每一个 ConcreteClass 都可以给出这些抽象方法的不同实现，从而使得顶级逻辑的实现各不相同。

class ConcreteClassA: AbstractClass
{
    public override void PrimitiveOperation1()
    {
        Console.WriteLine("A 方法1实现");
    }
    public override void PrimitiveOperation2()
    {
        Console.WriteLine("A 方法2实现");
    }
}
class ConcreteClassB: AbstractClass
{
    public override void PrimitiveOperation1()
    {
        Console.WriteLine("B 方法1实现");
    }
    public override void PrimitiveOperation2()
    {
        Console.WriteLine("B 方法2实现");
    }
}

二、模板方法模式的特点

是通过把不变的行为放到抽象类中，取出子类中的重复代码来体现它的优势。

三、举例

using System;
namespace Factory1
{
    class TestPaper{
        public void TestQuestion1(){
            Console.WriteLine("maybe TestQuestion1 [ ]a.A b.B c.C d.D");
            Console.WriteLine("answer: " + Answer1());

        }
        public void TestQuestion2()
        {
            Console.WriteLine("maybe TestQuestion2 [ ] a.A b.B c.C d.D");
            Console.WriteLine("answer: " + Answer2());

        }
        public void TestQuestion3()
        {
            Console.WriteLine("maybe TestQuestion3 [ ] a.A b.B c.C d.D");
            Console.WriteLine("answer: " + Answer3());
        }
        protected virtual string Answer1()
        {
            return "";
        }
        protected virtual string Answer2()
        {
            return "";
        }
        protected virtual string Answer3()
        {
            return "";
        }
    }
    class TestPaperA: TestPaper{


        protected override string Answer1()
        {
            return "b";
        }
        protected override string Answer2()
        {
            return "c";
        }
        protected override string Answer3()
        {
            return "a";
        }
    }

    class TestPaperB: TestPaper{


        protected override string Answer1()
        {
            return "c";
        }
        protected override string Answer2()
        {
            return "b";
        }
        protected override string Answer3()
        {
            return "a";
        }
    }
  //调用
    class MainClass
    {
        public static void Main (string[] args)
        {

            Console.WriteLine ("studentA");
            TestPaper studentA = new TestPaperA ();
            studentA.TestQuestion1 ();
            studentA.TestQuestion2 ();
            studentA.TestQuestion3 ();

            TestPaper studentB = new TestPaperB ();
            studentB.TestQuestion1 ();
            studentB.TestQuestion2 ();
            studentB.TestQuestion3 ();

            Console.Read ();
        }
    }
}

+结果：

studentA
maybe TestQuestion1 [ ]a.A b.B c.C d.D
answer: b
maybe TestQuestion2 [ ] a.A b.B c.C d.D
answer: c
maybe TestQuestion3 [ ] a.A b.B c.C d.D
answer: a
maybe TestQuestion1 [ ]a.A b.B c.C d.D
answer: c
maybe TestQuestion2 [ ] a.A b.B c.C d.D
answer: b
maybe TestQuestion3 [ ] a.A b.B c.C d.D
answer: a