php 设计模式（装饰器模式和原型模式组合）

最新推荐文章于 2025-08-30 11:58:02 发布

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本文介绍了一种软件设计模式——装饰器模式，并通过PHP编程语言中的绘图实例展示了如何利用该模式来动态地为对象添加职责。通过具体代码实现了不同装饰器对象对核心绘图功能的增强。

<?php
/**
 * 1.装饰器模式可以动态地 添加修改类的功能
 * 2.1个类完成一个功能如果要修改添加额外的功能，传统的编程模式需要写一个子类继承他，并重新实现类的方法
 * 3.使用装饰器模式，仅需在运行时添加-个装饰器对象即可实现，可以实现最大的灵活性
 */
interface DrawDecorator{
    public function afterDraw();
    public function beforeDraw();
}
class Dec implements DrawDecorator{
    public function __construct($color = 'red'){
        $this->color = $color;
    }
    public function afterDraw()
    {
        echo '</div>';
    }
    public function beforeDraw()
    {
      echo "<div style = 'color:{$this->color};'>";
    }
}
class Dec2 implements DrawDecorator{
    public function __construct($size = '20'){
        $this->size = $size;
    }
    public function afterDraw()
    {
        echo '</div>';
    }
    public function beforeDraw()
    {
        echo "<div style = 'font-size:{$this->size};'>";
    }
}

class Canvas
{
    public $data;
    protected $decorators = array();

    //初始化画布
    function init($width = 20, $height = 10)
    {
        $data = array();
        for($i = 0; $i < $height; $i++)
        {
            for($j = 0; $j < $width; $j++)
            {
                $data[$i][$j] = '*';
            }
        }
        $this->data = $data;
    }

    function addDecorator(DrawDecorator $decorator)
    {
        $this->decorators[] = $decorator;
    }

    function beforeDraw()
    {
        foreach($this->decorators as $decorator)
        {
            $decorator->beforeDraw();
        }
    }

    function afterDraw()
    {
        $decorators = array_reverse($this->decorators);
        foreach($decorators as $decorator)
        {
            $decorator->afterDraw();
        }
    }

    function draw()
    {
        $this->beforeDraw();
        foreach($this->data as $line)
        {
            foreach($line as $char)
            {
                echo $char;
            }
            echo "<br />\n";
        }
        $this->afterDraw();
    }

    function rect($a1, $a2, $b1, $b2)
    {
        foreach($this->data as $k1 => $line)
        {
            if ($k1 < $a1 or $k1 > $a2) continue;
            foreach($line as $k2 => $char)
            {
                if ($k2 < $b1 or $k2 > $b2) continue;
                $this->data[$k1][$k2] = '&nbsp;';
            }
        }
    }
}
$prototype = new Canvas();
$prototype->init();
$prototype->addDecorator(new Dec());

//原型模式
$ca1 = clone $prototype;
$ca1->rect(3, 6, 4, 12);
$ca1->draw();
echo '<br/>';
$prototype->addDecorator(new Dec2());
$ca2= clone $prototype;
$ca2->rect(1, 3, 2, 6);
$ca2->draw();