ArrayAccess 使用详解和实现配置化程序

ArrayAccess {
    //检查一个偏移位置是否存在
    abstract public boolean offsetExists ( mixed $offset );

    //获取一个偏移位置的值
    abstract public mixed offsetGet ( mixed $offset );

    //设置一个偏移位置的值
    abstract public void offsetSet ( mixed $offset , mixed $value );

    //复位一个偏移位置的值
    abstract public void offsetUnset ( mixed $offset );
}Copy

<?php
/**
 * Created by PhpStorm.
 * User: moell
 * Date: 16-10-30
 * Time: 下午8:49
 */

namespace User;

class User implements \ArrayAccess
{
    private $data = [];

    public function __construct()
    {
        $this->data =  [
            'name' => 'moell',
            'sex' => '男',
            'email' => 'moell@gmail.com'
        ];
    }

    /**
     * 检查指定字段数据是否存在
     *
     * @param $offset
     * @return bool
     */
    public function offsetExists($offset)
    {
        return isset($this->data[$offset]);
    }

    /**
     * 获取指定字段数据
     *
     * @param $offset
     * @return mixed
     */
    public function offsetGet($offset)
    {
        return $this->data[$offset];
    }

    /**
     * 设置指定字段数据
     *
     * @param $offset
     * @param $value
     * @return mixed
     */
    public function offsetSet($offset, $value)
    {
        return $this->data[$offset] = $value;
    }

    /**
     * 删除指定字段数据
     *
     * @param $offset
     */
    public function offsetUnset($offset)
    {
        unset($this->data[$offset]);
    }
}

$user = new User();

//获取用户的email
echo $user['email'].PHP_EOL;  // moell@gmail.com

//检查age是否存在
var_dump(isset($user['age'])); // bool(false)

//设置age
$user['age'] = 18;
echo $user['age'].PHP_EOL; //18

//删除age
unset($user['age']);
var_dump(isset($user['age'])); // bool(false)
Copy

<?php

return [
    'name' => 'app name',
    'version' => 'v1.0.0'
];Copy

<?php

return [
    'mysql' => [
        'host' => 'localhost',
        'user' => 'root',
        'password' => '12345678'
    ]
];Copy

<?php

namespace Config;

class Config implements \ArrayAccess
{
    private $config = [];

    private static $instance;

    private $path;

    private function __construct()
    {
        $this->path = __DIR__."/config/";
    }

    public static function instance()
    {
        if (!(self::$instance instanceof Config)) {
            self::$instance = new Config();
        }
        return self::$instance;
    }

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

    public function offsetGet($offset)
    {
        if (empty($this->config[$offset])) {
            $this->config[$offset] = require $this->path.$offset.".php";
        }
        return $this->config[$offset];
    }

    public function offsetSet($offset, $value)
    {
        throw new \Exception('不提供设置配置');
    }

    public function offsetUnset($offset)
    {
        throw new \Exception('不提供删除配置');
    }
}

$config = Config::instance();

//获取app.php 文件的 name
echo $config['app']['name'].PHP_EOL; //app name

//获取database.php文件mysql的user配置
echo $config['database']['mysql']['user'].PHP_EOL; // root
Copy