第一章 代码无错就是优 －－－简单工厂模式

1.简单工厂模式

  1. <?php 
  3. /**
  4.  * Operation 
  5.  */
  6. class Operation
  7. {
  8.     protected  $a = 0;
  9.     protected  $b = 0;
  11.     public function setA($a)
  12.     {
  13.         $this->a = $a;
  14.     }
  16.     public function setB($b)
  17.     {
  18.         $this->b = $b;
  19.     }
  21.     public function getResult()
  22.     {
  23.         $result = 0;
  24.         return $result;
  25.     }
  26. }
  28. /**
  29.  * Add 
  30.  */
  31. class OperationAdd extends Operation
  32. {
  33.     public function getResult()
  34.     {
  35.         return $this->a + $this->b;
  36.     }
  37. }
  39. /**
  40.  * Mul
  41.  */
  42. class OperationMul extends Operation
  43. {
  44.     public function getResult()
  45.     {
  46.         return $this->a * $this->b;
  47.     } 
  48. }
  50. /**
  51.  * Sub
  52.  */
  53. class OperationSub extends Operation
  54. {
  55.     public function getResult()
  56.     {
  57.         return $this->a - $this->b;
  58.     }
  59. }
  61. /**
  62.  * Div
  63.  */
  64. class OperationDiv extends Operation
  65. {
  66.     public function getResult()
  67.     {
  68.         return $this->a / $this->b;
  69.     }
  70. }
  72. /**
  73.  * Operation Factory
  74.  */
  75. class OperationFactory
  76. {
  77.     public static function createOperation($operation)
  78.     {
  79.         switch ($operation) {
  80.             case '+':
  81.                 $oper = new OperationAdd();
  82.                 break;
  83.             case '-':
  84.                 $oper = new OperationSub();
  85.                 break;
  86.             case '/':
  87.                 $oper = new OperationDiv();
  88.                 break;
  89.             case '*':
  90.                 $oper = new OperationMul();
  91.                 break;
  92.         }
  94.         return $oper;
  95.     }
  96. }
  98. // 客户端代码
  99. $operation = OperationFactory::createOperation('+');
  100. $operation->setA(1);
  101. $operation->setB(2);
  102. echo $operation->getResult() . PHP_EOL;

总结

学会通过分封装，继承，多态把程序的藕合度降低

复用，不是复制！

高内聚，低耦合

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