实例讲解PHP设计模式编程中的简单工厂模式

interface Fruit
{
public function grow();
public function harvest();
public function plant();
}

class Apple implements Fruit
{
private $_treeAge;
public function grow()
{
echo "Apple is growing.";
}
public function harvest()
{
echo "Apple has been harvested.";
}
public function plant()
{
echo "Apple has been planted.";
}
public function getTreeAge()
{
return $this->_treeAge;
}
public function setTreeAge($treeAge)
{
$this->_treeAge = (int) $treeAge;
}
}

class Grape implements Fruit
{
private $seedless;
public function grow()
{
echo "Grape is growing.";
}
public function harvest()
{
echo "Grape has been harvested.";
}
public function plant()
{
echo "Grape has been planted.";
}
public function getSeedless()
{
return $this->seedless;
}
public function setSeedless($seedless)
{
$this->seedless = (boolean) $seedless;
}
}

class Strawberry implements Fruit
{
public function grow()
{
echo "Strawberry is growing.";
}
public function harvest()
{
echo "Strawberry has been harvested.";
}
public function plant()
{
echo "Strawberry has been planted.";
}
}

class FruitGardener
{
public static function factory($which)
{
$which = strtolower($which);
if ($which == 'apple') {
return new Apple();
} elseif ($which == 'strawberry') {
return new Strawberry();
} elseif ($which == 'grape') {
return new Grape();
} else {
throw new BadFruitException('Bad fruit request');
}
}
}

class BadFruitException extends Exception
{
}

try {
FruitGardener::factory('apple');
FruitGardener::factory('grape');
FruitGardener::factory('strawberry');
//...
} catch (BadFruitException $e) {
//...
}

/**
 * 面向对象计算器
 * 思路：
 * 1、面向对象的基本，封装、继承、多太
 * 2、父类公用类
 * 3、各种运算类
 */
 
/**
 * 基类，运算类
 * 只提供基本数据，不参与运算
 */
 
class Operation {
  
 // 第一个数
 public $first_num = 0;
  
 // 第二个数
 public $second_num = 0;
  
 /**
  * 获取结果，其他类覆盖此方法
  * @return double $result
  */
 public function getResult() {
  $result = 0.00;
   
  return $result;
 }
}
 
/**
 * 加法类
 */
class OperationAdd extends Operation {
 /**
  * 覆盖父类，实现加法算法
  */
 public function getResult() {
  $result = 0;
  return $this->first_num + $this->second_num;
 }
}
 
/**
 * 减法类
 *
 */
class OperationSub extends Operation {
 /**
  * 覆盖父类，实现加法算法
  */
 public function getResult() {
  $result = 0;
  return $this->first_num - $this->second_num;
 }
}
 
/**
 * 乘法类
 *
 */
class OperationMul extends Operation {
 /**
  * 覆盖父类，实现加法算法
  */
 public function getResult() {
  $result = 0;
  return $this->first_num * $this->second_num;
 }
}
 
/**
 * 除类
 *
 */
class OperationDiv extends Operation {
 /**
  * 覆盖父类，实现加法算法
  */
 public function getResult() {
  $result = 0;
   
  if ($this->second_num == 0) {
   throw new Exception('除法操作第二个参数不能为零!');
   return 0;
  }
   
  return $this->first_num / $this->second_num;
 }
}
 
/**
 * 工厂类
 */
class OperationFactory {
 /**
  * 工厂函数
  * @param string $operation
  * @return object
  */
 public function createOperation($operation) {
  $oper = null;
   
  switch($operation) {
   case '+':
    $oper = new OperationAdd();
    break;
   case '-':
    $oper = new OperationSub();
    break;
   case '*':
    $oper = new OperationMul();
    break;
   case '/':
    $oper = new OperationDiv();
    break;
   default:
    return 0;
  }
  return $oper;
 }
}
 
 
$operation = new OperationFactory();
$oper = $operation->createOperation('/');
 
$oper->first_num = 10;
$oper->second_num = 20;
var_dump($oper->getResult());