原型模式-创建对象

原型模式

操作：先创建好一个原型对象，然后通过clone 原型对象来创建新的对象。这就免去了类创建时重复的初始化操作。

原型模式适用于大对象的创建。如果每次new 就会消耗很大，原型模式仅需要内存拷贝即可。

index.php 中

$prototype = new Imooc\Canvas();
$prototype->init();              //需要做很多很复杂的，耗时的处理
$prototype->rect(3, 6, 4, 12);
$prototype->draw();
echo "==================<br/>\n";

$canvas2 = clone $prototype;
$canvas2->rect(1,3, 2, 6);  //和直接new 相比省掉 了init
$canvas2->draw();

Canvas.php 中

<?php
/**
 * Created by PhpStorm.
 */

namespace Imooc;


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

    public 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;
    }

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

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

    function afterDraw(){
        //装饰器反转； 后进先出；
        $decorators = array_reverse($this->decorators);
        foreach($decorators as $decorator){
            $decorator->afterDraw();
        }
    }

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

        //$this->afterDraw();
    }
}

原型模式-创建对象

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