將某個(gè)類(lèi)的接口轉(zhuǎn)換成與另一個(gè)接口兼容。適配器通過(guò)將原始接口進(jìn)行轉(zhuǎn)換,給用戶提供一個(gè)兼容接口,使得原來(lái)因?yàn)榻涌诓煌鵁o(wú)法一起使用的類(lèi)可以得到兼容。
Book.php
<?php
declare(strict_types=1);
namespace DesignPatterns\Structural\Adapter;
interface Book
{
public function turnPage();
public function open();
public function getPage(): int;
}
PaperBook.php
<?php
declare(strict_types=1);
namespace DesignPatterns\Structural\Adapter;
class PaperBook implements Book
{
private int $page;
public function open(): void
{
$this->page = 1;
}
public function turnPage(): void
{
$this->page++;
}
public function getPage(): int
{
return $this->page;
}
}
EBook.php
<?php
declare(strict_types=1);
namespace DesignPatterns\Structural\Adapter;
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;
}
EBookAdapter.php
<?php
declare(strict_types=1);
namespace DesignPatterns\Structural\Adapter;
/**
* This is the adapter here. Notice it implements Book,
* therefore you don't have to change the code of the client which is using a Book
*/
class EBookAdapter implements Book
{
public function __construct(protected 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
*/
public function getPage(): int
{
return $this->eBook->getPage()[0];
}
}
Kindle.php
<?php
declare(strict_types=1);
namespace DesignPatterns\Structural\Adapter;
/**
* this is the adapted class. In production code, this could be a class from another package, some vendor code.
* Notice that it uses another naming scheme and the implementation does something similar but in another way
*/
class Kindle implements EBook
{
private int $page = 1;
private int $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];
}
}
Tests/AdapterTest.php
<?php declare(strict_types=1); namespace DesignPatterns\Structural\Adapter\Tests; use DesignPatterns\Structural\Adapter\PaperBook; use DesignPatterns\Structural\Adapter\EBookAdapter; use DesignPatterns\Structural\Adapter\Kindle; use PHPUnit\Framework\TestCase; class AdapterTest extends TestCase { public function testCanTurnPageOnBook() { $book = new PaperBook(); $book->open(); $book->turnPage(); $this->assertSame(2, $book->getPage()); } public function testCanTurnPageOnKindleLikeInANormalBook() { $kindle = new Kindle(); $book = new EBookAdapter($kindle); $book->open(); $book->turnPage(); $this->assertSame(2, $book->getPage()); } }
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