配置与设计模式

1.PHP中使用ArrayAccess实现配置文件的加载

$config = new \IMooc\Config(__DIR__.‘/configs‘);var_dump($config[‘controller‘]);

<?phpnamespace IMooc;

class Config implements \ArrayAccess{    protected $path;    protected $configs = array();

function __construct($path)    {        $this->path = $path;    }

public function offsetExists($key)    {        return isset($this->configs[$key]);    }

public function offsetGet($key)    {        if (empty($this->configs[$key]))        {            $file_path = $this->path.‘/‘.$key.‘.php‘;            $config = require $file_path;            $this->configs[$key] = $config;            return $this->configs[$key];        }    }

public function offsetSet($Key, $value)    {        throw new \Exception("cannot write config file.");    }

public function offsetUnset($key)    {        unset($this->configs[$key]);    }}

<?phpnamespace Configs;$config = array(    ‘home‘ => array(        ‘decorator‘ => array(            ‘IMooc\Decorator\Template‘,        ),    ),    ‘default‘ => ‘hello world‘,);return $config;


2.在工厂方法中读取配置，生成可配置化的对象
$db = \IMooc\Factory::getDatabase();

<?php
namespace IMooc;

class Factory{

static function getDatabase($id = ‘master‘)    {        $key = ‘database_‘.$id;
        if ($id == ‘slave‘)
        {
            $slaves = Application::getInstance()->config[‘database‘][‘slave‘];
            $db_conf = $slaves[array_rand($slaves)];
        }
        else
        {
            $db_conf = Application::getInstance()->config[‘database‘]
[$id];
        }
        $db = Register::get($key);
        if (!$db)
        {            $db = new Database\MySQLi();
            $db->connect($db_conf[‘host‘], $db_conf[‘user‘], $db_conf[‘password‘], $db_conf[‘dbname‘]);
            Register::set($key, $db);
        }
        return $db;    }}
3.使用装饰器模式实现权限验证，模板渲染，JSON串化
4.使用观察者模式实现数据更新事件的一系列更新操作
5.使用代理模式实现数据的主从自动切换

来自为知笔记(Wiz)