<?php

//Ioc ————  设计方式

//控制反转 Inversion of Control

//依赖关系的转移

//依赖抽象而非实践

//用于解决高层应用依赖 底层组件，软件移植性差（修改困难）的问题

//实例:

/*

class soft{

    private $writer;

    public function __construct(){

        $this->writer = new FloppyWriter;

    }

    public function save(){

        $this->writer->SaveToFloppy();

    }

}

//造成高层对底层的依赖__使程序无法重用 不好的设计

class FloppyWriter{

    public function saveToFloppy(){

        echo __METHOD__;

    }

}

$soft = new soft;

$soft->save()

*/

##########################改进##########################

//定义一个接口约定

interface IDeviceWriter

{

    public function saveToDevice();

}

class soft{

    private $_writer;

    public function setWriter($name){

        $this->_writer = $name;

    }

    public function save(){

        $this->_writer->saveToDevice();

    }

}

//软盘储存

class FoppyWriter implements IDeviceWriter{

    public function saveToDevice(){

        echo __METHOD__;

    }

}

//USB储存

class USBWriter implements IDeviceWriter{

    public function saveToDevice(){

        echo __METHOD__;

    }

}

//将高层依赖 转移到 "依赖注入"

$soft= new soft();

$writer=  new USBWriter;

$soft->setWriter($writer);

$soft->save();