橋模式

<?php 

declare(strict_types=1);

// php 技術羣：781742505

// 多個 Formatters 抽象出 Formatter 接口
// 多個 Services 抽象出 Service 接口
// 兩個接口之間有座橋，將兩個接口的所有實例可以任意互聯。
/**
 * Interface Formatter
 */
interface Formatter
{
    /**
     * @param string $text
     *
     * @return string
     */
    public function format(string $text): string;
}


/**
 * Class Service
 *
 * @package DesignPatterns\Structural\Bridge
 */
abstract class Service
{
    /**
     * @var Formatter
     */
    protected $implementation;

    /**
     * @param Formatter $printer
     */
    public function __construct(Formatter $printer)
    {
        $this->implementation = $printer;
    }

    /**
     * @param Formatter $printer
     */
    public function setImplementation(Formatter $printer)
    {
        $this->implementation = $printer;
    }

    /**
     * @return string
     */
    abstract public function get(): string;
}

/**
 * Class HtmlFormatter
 *
 * @package DesignPatterns\Structural\Bridge
 */
class HtmlFormatter implements Formatter
{
    /**
     * @param string $text
     *
     * @return string
     */
    public function format(string $text): string
    {
        return sprintf('<p>%s</p>', $text);
    }
}

/**
 * Class PlainTextFormatter
 *
 * @package DesignPatterns\Structural\Bridge
 */
class PlainTextFormatter implements Formatter
{
    /**
     * @param string $text
     *
     * @return string
     */
    public function format(string $text): string
    {
        return "$text";
    }
}

/**
 * Class PingService
 *
 * @package DesignPatterns\Structural\Bridge
 */
class PingService extends Service
{
    /**
     * @return string
     */
    public function get(): string
    {
        return $this->implementation->format("pong");
    }
}

/**
 * Class HelloWorldService
 *
 * @package DesignPatterns\Structural\Bridge
 */
class HelloWorldService extends Service
{
    /**
     * @return string
     */
    public function get(): string
    {
        return $this->implementation->format('Hello World');
    }
}

echo (new HelloWorldService(new PlainTextFormatter()))->get();
echo (new HelloWorldService(new HtmlFormatter()))->get();
echo (new PingService(new PlainTextFormatter()))->get();
echo (new PingService(new HtmlFormatter()))->get();