简单工厂模式

 使用简单工厂实现计算器

namespace SimpleFactory\OperationClass;
/**
 * 运算抽象类
 * @author struggle
 * @verison 2012-5-28
 */
abstract  class Operation{
    /**
     * 计算结果
     * @param int/float $param1 参数1
     * @param int/float $param2 参数2
     */
    public abstract  function getResult($param1,$param2);
}
/**
 * 加法类
 * @author struggle
 * @verison 2012-5-24
 */
class OperationAdd extends Operation {

    public function getResult($param1,$param2){
        return $param1 + $param2;
    }
}
/**
 * 减法类
 * @author struggle
 * @verison 2012-5-24
 */
class OperationSub extends Operation {

    public function getResult($param1,$param2){
        return $param1 - $param2;
    }
}
/**
 * 乘法类
 * @author struggle
 * @verison 2012-5-24
 */
class OperationMul extends Operation {
    /**
     * 返回乘法结果
     */
    public function getResult($param1,$param2){
        return $param1 * $param2;
    }
}
/**
 * 除法类
 * @author struggle
 * @verison 2012-5-24
 */
class OperationDiv extends Operation {
    /**
     * 返回乘法结果
     */
    public function getResult($param1,$param2){
        if($param2 == 0){
            throw new \Exception('被除数不能为 0');
        }
        return $param1 /$param2;
    }
}

工厂类：

namespace  SimpleFactory;
use SimpleFactory\OperationClass;
/**
 * 工厂类
 * @author struggle
 * @verison 2012-5-24
 */
class OperationFactory {
    /**
     * 创建操作类
     * @param string $string
     */
    public static  function createOpertaion($string){
         $operation = '';
        switch ($string) {
            case '+':
               $operation = new OperationClass\OperationAdd();
               break;
            case '-':
                $operation = new OperationClass\OperationSub();
                break;
            case '*':
                $operation = new OperationClass\OperationMul();
                break;
            case '/':
                $operation = new OperationClass\OperationDiv();
                break;
            default:
                throw  new \Exception("没有此运算符");
            break;
        }
        return $operation;
    }
}

客户端调用程序：

/**
 * 工厂设计模式
 */
use SimpleFactory\OperationFactory;
define('ROOT_PATH',dirname(dirname(__FILE__)).'/');
/**
 * 自动加载类文件
 * @param $class
 */
function __autoload($class){
    if(strpos($class,'OperationClass')){
        $class_path = substr($class,0,strrpos($class,'\\'));
    }else{
        $class_path = str_replace('\\','/',$class);
    }
    include_once ROOT_PATH.$class_path.'.class.php';
}
//调用工厂方法生成运算对象
$oper = OperationFactory::createOpertaion('/');
$result = $oper->getResult(1,10);
var_dump($result);

UML类图：

使用VISO做的类图有些差