模板模式

当我们要完成在某一细节层次一致的一个过程或一系列步骤，但其个别步骤在更详细的层次上的实现可能不同时,我们通常考虑用模板方法模式来处理

<?php
/**
 * Created by PhpStorm.
 * User: Administrator
 * Date: 2018/2/7
 * Time: 16:47
 */

namespace frontendmodels;


class TestPaper
{

    public  function TestQuestion1(){

        echo '问题1<br>';

        echo '答案为'.$this->Answer1().'<br>';
    }
    public  function TestQuestion2(){

        echo '问题2<br>';

        echo '答案为'.$this->Answer2().'<br>';
    }
    public  function TestQuestion3(){

        echo '问题3<br>';

        echo '答案为'.$this->Answer3().'<br>';
    }

    public function Answer1(){

        return '';
    }
    public function Answer2(){

        return '';
    }
    public function Answer3(){

        return '';
    }


}

<?php
/**
 * Created by PhpStorm.
 * User: Administrator
 * Date: 2018/2/7
 * Time: 16:53
 */

namespace frontendmodels;


class TestPaperA extends TestPaper
{

    public function Answer1(){

        return 'A';
    }
    public function Answer2(){

        return 'B';
    }
    public function Answer3(){

        return 'C';
    }

}

<?php
/**
 * Created by PhpStorm.
 * User: Administrator
 * Date: 2018/2/7
 * Time: 16:54
 */

namespace frontendmodels;


class TestPaperB extends TestPaper
{
    public function Answer1(){

        return 'C';
    }
    public function Answer2(){

        return 'A';
    }
    public function Answer3(){

        return 'B';
    }

}

$test1 = new TestPaperA();

$test2 = new TestPaperB();

$test1->TestQuestion1();
$test1->TestQuestion2();
$test1->TestQuestion3();

$test2->TestQuestion1();
$test2->TestQuestion2();
$test2->TestQuestion3();

模板方法模式是通过把不变行为搬移到超类,去除子类中的重复代码来提现它的优势。有时候我们会遇到由一系列步骤构成的过程需要执行。这个过程从高层次上看是相同的,但有些步骤的实现可能不同。这时候,我们通常就应该要考虑用模板方法模式了。