14-享元模式.php

<?php

declare(strict_types=1);

/*
 * This file is modified from `xiaohuangniu/26`.
 *
 * @see https://github.com/xiaohuangniu/26
 */

header('Content-type: text/html; charset=utf-8');

// 动物接口
interface AnimalInterface
{
    public function getType();
}

/**
 * 创建 - 鸡模型.
 */
class ChiCken implements AnimalInterface
{
    public function getType()
    {
        echo '这是一只鸡~'.PHP_EOL;
    }
}

/**
 * 创建 - 猪模型.
 */
class Pig implements AnimalInterface
{
    public function getType()
    {
        echo '这是一只猪~'.PHP_EOL;
    }
}

// 农场缓存池
class Farm
{
    private $_farmMap = []; // 对象缓存池

    public function Produce($type)
    {
        // 对象缓存池判断
        if (key_exists($type, $this->_farmMap)) {
            echo '来自缓存池-> ';

            return $this->_farmMap[$type]; // 返回缓存
        }
        // 建立缓存
        switch ($type) {
            case 'chicken':
                return $this->_farmMap[$type] = new Chicken();
                break;
            case 'pig':
                return $this->_farmMap[$type] = new Pig();
                break;
        }
    }
}

// 初始化一个缓存池
$farm = new Farm();
// 成产一只鸡
$farm->Produce('chicken')->getType();
// 再生产一只鸡
$farm->Produce('chicken')->getType();
// 再生产一只鸡
$farm->Produce('chicken')->getType();
// 生产一只猪
$farm->Produce('pig')->getType();
// 再生产一只猪
$farm->Produce('pig')->getType();
// 再生产一只猪
$farm->Produce('pig')->getType();