适配器或包装器模式

解决两个接口不兼容的问题。

// php 技术群：781742505

<?php 

declare(strict_types=1);

interface Book
{
    public function turnPage();

    public function open();

    public function getPage(): int;
}



class PaperBook implements Book
{
    /**
     * @var int
     */
    private $page;

    public function open()
    {
        $this->page = 1;
    }

    public function turnPage()
    {
        $this->page++;
    }

    public function getPage(): int
    {
        return $this->page;
    }
}



interface EBook
{
    public function unlock();

    public function pressNext();

    /**
     * returns current page and total number of pages, like [10, 100] is page 10 of 100
     *
     * @return int[]
     */
    public function getPage(): array;
}



class Kindle implements EBook
{
    /**
     * @var int
     */
    private $page = 1;

    /**
     * @var int
     */
    private $totalPages = 100;

    public function pressNext()
    {
        $this->page++;
    }

    public function unlock()
    {
    }

    /**
     * returns current page and total number of pages, like [10, 100] is page 10 of 100
     *
     * @return int[]
     */
    public function getPage(): array
    {
        return [$this->page, $this->totalPages];
    }
}



class EBookAdapter implements Book
{
    /**
     * @var EBook
     */
    protected $eBook;

    /**
     * @param EBook $eBook
     */
    public function __construct(EBook $eBook)
    {
        $this->eBook = $eBook;
    }

    /**
     * This class makes the proper translation from one interface to another.
     */
    public function open()
    {
        $this->eBook->unlock();
    }

    public function turnPage()
    {
        $this->eBook->pressNext();
    }

    /**
     * notice the adapted behavior here: EBook::getPage() will return two integers, but Book
     * supports only a current page getter, so we adapt the behavior here
     *
     * @return int
     */
    public function getPage(): int
    {
        return $this->eBook->getPage()[0];
    }
}


// 使用起来
$book = new PaperBook();
$book->open();
$book->turnPage();


$kindle = new Kindle();
$book = new EBookAdapter($kindle);
$book->open();
$book->turnPage();