简单工厂模式实例与讲解

来源：互联网发布：递四方知乎编辑：程序博客网时间：2024/05/29 13:17

abstract class ApptEncoder{    abstract function encode();}class BloggsApptEncoder extends ApptEncoder{    function encode(){        return 'this is bloggs object';    }}class MegaApptEncoder extends ApptEncoder{    function encode(){        return 'this is mega object';    }}class CommsManager{    const BLOGGS = 1;    const MEAG = 2;    private $mode = 1;    function __construct($mode){        $this->mode;    }    function getAppEncoder(){        switch ($this->mode){            case (self::BLOGGS):                return new BloggsApptEncoder();            case (self::MEAG):                return new MegaApptEncoder();        }    }}$comms = new CommsManager(CommsManager::MEAG);$apptEncoder = $comms->getAppEncoder();print_r($apptEncoder->encode());    //输出：this is bloggs object

以上属于典型的简单工厂模式，可以适用于简单的运行模式，存在一定的缺陷，当我们需要在CommsManager中新增一个模式方法时，我们不得不再次进行模式的判断，CommsManager如下（我们新增了getHeaderText）：

class CommsManager{    const BLOGGS = 1;    const MEAG = 2;    private $mode = 1;    function __construct($mode){        $this->mode;    }    function getAppEncoder(){        switch ($this->mode){            case (self::BLOGGS):                return new BloggsApptEncoder();            case (self::MEAG):                return new MegaApptEncoder();        }    }    function getHeaderText(){        switch ($this->mode){            case (self::BLOGGS):                return 'this is bloggs headerText';            case (self::MEAG):                return 'this is meag headerText';        }    }}

从上面我们可以看出，我们使用了重复的代码判断条件，我们可以对此进行简化和进一步的改进，也就是我们的工厂方法模式

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